Physic Basic Flashcards
1
Q
A
2
Q
State Newton’s First Law of Motion briefly.
A
An object remains at rest or in uniform motion unless acted on by an external force.
3
Q
Write the formula for average velocity.
A
v_avg = (Δx)/(Δt).
4
Q
If acceleration is constant, what is the formula for final velocity v given initial velocity v₀ and acceleration a over time t?
A
v = v₀ + a·t.
5
Q
Formula for displacement under constant acceleration, starting from rest?
A
x = (1/2) a t².
6
Q
State Newton’s Second Law in a formula.
A
F = m·a.
7
Q
Write the formula for weight (on Earth’s surface).
A
W = m·g.
8
Q
What does g typically approximate near Earth’s surface?
A
9.8 m/s².
9
Q
State the formula for frictional force for kinetic friction.
A
F_f = μ_k N (where N is normal force).
10
Q
What is centripetal acceleration formula for uniform circular motion?
A
a_c = v²/r.
11
Q
State Newton’s Third Law of Motion.
A
For every action, there is an equal and opposite reaction.
12
Q
Formula for momentum p of a mass m with velocity v?
A
p = m·v.
13
Q
What is impulse defined as?
A
Change in momentum (Δp), or Force × time interval.
14
Q
In an inelastic collision, which quantity is conserved: momentum, kinetic energy, or both?
A
Momentum is conserved, kinetic energy is not.
15
Q
What is the formula for centripetal force for uniform circular motion?
A
F_c = m·v²/r.
16
Q
Define uniform acceleration in terms of velocity.
A
Velocity changes at a constant rate over time.
17
Q
If a projectile is launched horizontally at speed v, ignoring air resistance, how does its horizontal velocity change?
A
Remains constant (no horizontal acceleration).
18
Q
If a projectile is launched straight up with speed v₀, ignoring air resistance, what is its speed at the top of its path?
A
0 m/s (instantaneously).
19
Q
What is terminal velocity in free fall with air resistance?
A
The constant velocity where drag force = weight.
20
Q
According to Newton’s law of universal gravitation, F_g=?
A
F_g=G(m₁m₂)/r².
21
Q
On an inclined plane with angle θ, ignoring friction, acceleration of a block down the slope is?
A
g sinθ.
22
Q
Define Work in physics, W=?
A
W=F·d·cos(θ) (force × displacement × cos of angle).
23
Q
Kinetic Energy (KE) formula for mass m moving at speed v?
A
KE = (1/2)m v².
24
Q
Potential Energy (PE) near Earth’s surface with mass m at height h?
A
PE = m g h.
25
Law of Conservation of Energy in closed system states...?
Total energy remains constant (KE + PE + other forms = constant).
26
Work-Energy Theorem in short form?
Net Work done = ΔKinetic Energy.
27
Power P is defined as?
Work done per unit time: P = W / t.
28
SI unit of Work or Energy is...?
Joule (J).
29
SI unit of Power is...?
Watt (W), i.e. Joule per second.
30
Mechanical advantage of a simple machine concept?
Ratio of output force to input force.
31
Formula for elastic potential energy in a spring (Hooke’s Law) with constant k?
PE_spring= (1/2)k x².
32
Hooke’s Law for spring force, F_s=?
F_s=−k x (restoring force).
33
Gravitational potential energy between masses (Newton’s universal)? (In general form)
U=−G(m₁m₂)/r.
34
If an object’s speed doubles, its kinetic energy changes by factor of...?
4 (since KE∝v²).
35
Work done by friction is positive or negative if motion is opposite direction of friction?
Negative.
36
If no friction, total mechanical energy is constant: T/F?
True.
37
Potential energy stored in an elevated mass is mgh. Doubling height does what to potential energy?
Doubles it.
38
Scalar or vector? Work is a...?
Scalar.
39
Calculate power if 100 J of work is done in 5 s.
Power=100/5=20 W.
40
One horsepower is about 746 watts: T/F?
True.
41
If Net Work=0, how does speed change?
It doesn’t change (no change in KE).
42
Momentum p= m·v. If both mass and velocity double, momentum changes by factor...?
4.
43
Impulse J=F·Δt. Also equals Δp, T/F?
True.
44
In an elastic collision, which two quantities are conserved?
Momentum and kinetic energy.
45
Unit of momentum in SI?
kg·m/s.
46
If total external force on a system = 0, total momentum is...?
Constant (conserved).
47
If two masses stick together after collision, it’s called...?
Perfectly inelastic collision.
48
State the formula for ballistic pendulum or typical inelastic collision in short.
m₁v₁ + m₂v₂= (m₁+m₂)v_final.
49
If object’s momentum is zero, is speed definitely zero?
Yes, if mass is not zero.
50
Time to stop an object with certain impulse is shorter if force is bigger or smaller?
Bigger force => shorter time.
51
Collision with identical masses in a 1D elastic scenario: if one is at rest, the moving mass stops, the other moves with same speed. T/F?
True (the classic Newton’s cradle effect).
52
Define frequency f in terms of period T?
f=1/T.
53
Wave speed v=?
v= λ f (wavelength×frequency).
54
Hooke’s Law for a simple harmonic oscillator: F=?
F=−kx (restoring force).
55
Period of a simple pendulum (small angles) T=?
T=2π√(L/g).
56
Period of a mass-spring system T=?
T=2π√(m/k).
57
The amplitude of a wave is the maximum displacement from equilibrium. T/F?
True.
58
In a transverse wave, the medium vibrates perpendicular to wave direction. T/F?
True.
59
In a longitudinal wave, the medium vibrates parallel to wave direction. T/F?
True.
60
Resonance occurs when driving frequency = natural frequency. T/F?
True.
61
Sound is typically a longitudinal wave in air, T/F?
True.
62
Zeroth Law of Thermodynamics states...?
If A is in thermal equilibrium with B, and B with C, then A and C are in equilibrium.
63
First Law of Thermodynamics formula?
ΔU= Q−W (change in internal energy= heat in−work out).
64
Second Law of Thermodynamics in short?
Entropy of an isolated system never decreases.
65
Define temperature in a basic sense.
Measure of average kinetic energy of particles.
66
Heat conduction formula (Fourier’s Law) in short?
Q/t= kA (ΔT/Δx).
67
SI unit of heat or energy is the Joule: T/F?
True.
68
Define specific heat capacity c.
Amount of heat needed to raise 1 kg of a substance by 1°C.
69
In isobaric process, pressure is constant. T/F?
True.
70
In an adiabatic process, what is Q?
Q=0 (no heat exchange).
71
At phase change (e.g. melting), temperature remains constant as energy changes phase: T/F?
True.
72
Coulomb’s Law for electrostatic force F=?
F= k (q₁ q₂)/r².
73
Value of Coulomb’s constant k≈?
8.99×10⁹ N·m²/C².
74
Electric field E due to point charge Q at distance r=?
E= k Q/r².
75
Definition: Electric current I=?
Charge flow per unit time: I=ΔQ/Δt.
76
Ohm’s Law formula?
V= I R.
77
SI unit of Resistance is...?
Ohm (Ω).
78
In series circuit, how do we add resistances R?
R_total=R₁+R₂+....
79
In parallel circuit, how do we add resistances?
1/R_total=1/R₁+1/R₂+....
80
SI unit of electric charge is...?
Coulomb (C).
81
Definition of electric power P?
P= I V= I² R= V²/R.
82
Magnetic force on a moving charge q with velocity v in magnetic field B, F=?
F= q v B sin(θ).
83
Right-hand rule for magnetic force if charge is positive: T/F?
True, use right-hand rule for direction.
84
Gauss’s Law for electric fields: ∮ E · dA=?
Q_enc/ε₀.
85
Ampere’s Law in magnetism: ∮ B · dl=?
μ₀ I_enc (for steady currents).
86
Faraday’s Law of Induction in short?
EMF=−dΦ/dt (negative sign is Lenz's Law).
87
Lenz’s Law indicates the induced current direction does what?
Opposes the change in magnetic flux.
88
Capacitance of parallel-plate capacitor: C=?
ε₀ (A/d).
89
Energy stored in a capacitor formula, U=?
U= (1/2) C V².
90
Definition of electromotive force (emf) concept?
Voltage provided by a source (like battery).
91
If a circuit has resistance R and supply V, then I=?
I= V/R.
92
Speed of light in vacuum c≈?
3×10⁸ m/s.
93
Einstein’s mass-energy equivalence formula?
E= m c².
94
Photoelectric effect main formula?
K_max= h f − φ (work function).
95
Planck’s constant h≈?
6.626×10⁻³⁴ J·s.
96
Definition of half-life t₁/₂ in radioactivity?
Time for half of a radioactive sample to decay.
97
Bohr model for hydrogen: electron orbits with quantized angular momentum T/F?
True.
98
Heisenberg’s Uncertainty Principle in short?
Δx Δp ≥ ħ/2.
99
De Broglie wavelength λ=?
λ= h/p= h/(m v).
100
Thermal radiation peak shifts with temperature (Wien’s Law) T/F?
True, λ_peak∝1/T.
101
Definition: Mach number=?
Object speed / speed of sound in medium.
102
Define displacement in kinematics.
The net change in position from an initial point to a final point, a vector quantity.
103
Define speed in physics.
The rate of distance traveled per unit time, a scalar quantity (no direction).
104
Define velocity.
Displacement per unit time, a vector quantity with magnitude and direction.
105
Define acceleration.
The rate of change of velocity over time.
106
Define inertia.
The property of an object to resist changes in its state of motion.
107
Define net force.
The vector sum of all forces acting on an object.
108
Define equilibrium (mechanical).
State where net force on an object is zero, so its acceleration is zero.
109
Define normal force.
Perpendicular contact force exerted by a surface on an object.
110
Define friction force.
A resistive force that opposes relative motion between surfaces in contact.
111
Define terminal velocity.
Constant velocity reached by a falling object when drag force equals weight.
112
Define momentum.
Product of mass and velocity (p = m·v), a vector.
113
Define impulse.
Change in momentum, or force multiplied by the time interval (Δp).
114
Define collision (in physics).
An event where two or more bodies exert forces on each other in a relatively short time.
115
Define elastic collision.
A collision where total kinetic energy and momentum are both conserved.
116
Define inelastic collision.
A collision where momentum is conserved but kinetic energy is not.
117
Define work (physics definition).
Force applied over a distance in the direction of displacement (W=F·d·cosθ).
118
Define power (physics).
The rate at which work is done or energy is transferred (P=W/t).
119
Define kinetic energy.
Energy due to an object’s motion, (1/2)mv².
120
Define potential energy.
Stored energy based on position or configuration (e.g., mgh for gravity).
121
Define mechanical energy.
Sum of kinetic and potential energies in a system.
122
Define efficiency (of a machine).
Ratio of useful work output to total energy input, typically a percentage.
123
Define amplitude (in waves or oscillations).
Maximum displacement from equilibrium position.
124
Define period (wave or oscillation).
Time for one complete cycle or oscillation.
125
Define frequency (waves).
Number of oscillations or cycles per unit time (f=1/T).
126
Define wavelength (λ).
Distance between consecutive identical points (e.g., crest to crest) in a wave.
127
Define transverse wave.
A wave where the medium’s displacement is perpendicular to wave propagation direction.
128
Define longitudinal wave.
A wave where the medium’s displacement is parallel to wave propagation direction (e.g., sound).
129
Define resonance.
A phenomenon where a system oscillates at maximum amplitude at its natural frequency.
130
Define node (in a standing wave).
Point of zero amplitude where destructive interference is consistent.
131
Define antinode (in a standing wave).
Point of maximum amplitude where constructive interference is consistent.
132
Define temperature in thermodynamics.
A measure of average kinetic energy of the particles in a substance.
133
Define internal energy (U) of a system.
The total microscopic kinetic and potential energies of all particles in a system.
134
Define heat (Q).
Thermal energy transfer from one body to another due to temperature difference.
135
Define specific heat capacity.
Amount of heat needed to raise 1 kg of a substance by 1°C (or 1 K).
136
Define latent heat.
Heat required for a phase change without temperature change.
137
Define conduction (heat transfer).
Transfer of heat via direct molecular collisions within a material.
138
Define convection (heat transfer).
Transfer of heat via fluid motion (e.g., warm air rising).
139
Define radiation (heat transfer).
Transfer of heat through electromagnetic waves (no medium needed).
140
Define entropy.
A measure of disorder or randomness in a system.
141
Define isothermal process.
Thermodynamic process at constant temperature.
142
Define electric charge.
A fundamental property (positive or negative) that causes electromagnetic interactions.
143
Define electric field E.
Region around a charge where another charge experiences force (E=F/q).
144
Define electric potential (V).
Electric potential energy per unit charge at a point in an electric field.
145
Define capacitor.
Device that stores electric charge and energy in an electric field.
146
Define electric current (I).
The rate of flow of electric charge, measured in Amperes (A).
147
Define resistance (R).
Opposition to current flow in a conductor, measured in ohms (Ω).
148
Define magnetic field B.
A field surrounding moving charges or magnetic materials that exerts force on other charges or magnets.
149
Define electromagnetic induction.
Creation of an EMF (voltage) by changing magnetic flux through a circuit.
150
Define transformer (in AC circuits).
Device that changes voltage levels via electromagnetic induction between coils.
151
Define photon (in modern physics).
A quantum of electromagnetic radiation, carrying energy E=hf.
152
Kinematic equation for constant acceleration: final velocity v?
v = v₀ + a t
153
Kinematic equation for displacement under constant acceleration (from rest)?
x = (1/2) a t²
154
Kinematic equation: x − x₀ = v₀ t + (1/2) a t²?
Yes, for constant acceleration, general form of displacement.
155
Another kinematic formula: v² = v₀² + 2a(x − x₀)?
Yes, relates velocities, acceleration, and displacement.
156
Newton’s Second Law in formula form?
F_net = m a
157
Friction force for kinetic friction?
F_f = μ_k N
158
Friction force for static friction (max)?
F_f(max)= μ_s N
159
Weight near Earth’s surface: W=?
m g (g≈9.8 m/s²)
160
Centripetal acceleration formula a_c=?
a_c= v² / r
161
Centripetal force formula F_c=?
F_c= m (v²/r) (points radially inward)
162
Impulse formula: J=?
J= F Δt= Δp (change in momentum)
163
Momentum p=?
p= m v
164
Work done by constant force: W=?
W= F d cos(θ)
165
Kinetic energy: KE=?
(1/2) m v²
166
Gravitational potential energy near Earth: PE=?
m g h
167
Spring potential energy: PE_spring=?
(1/2) k x²
168
Hooke’s Law for spring force: F_s=?
−k x
169
Power: P=?
Work / time = (W/t)= F v (if force and velocity parallel)
170
Mechanical energy (no friction): E=?
E= KE + PE= constant (if no nonconservative forces)
171
Momentum conservation formula in collisions?
m₁v₁ + m₂v₂= m₁v₁' + m₂v₂' (assuming no external net force)
172
Period of a simple pendulum (small angle): T=?
T= 2π √(L/g)
173
Period of a mass-spring oscillator: T=?
T= 2π √(m/k)
174
Wave speed formula: v=?
v= λ f (wavelength × frequency)
175
Snell’s Law for refraction: n₁ sinθ₁=?
n₂ sinθ₂
176
Doppler effect for sound (source stationary, observer moving): f'=?
f' = (v ± v_obs)/(v) × f (sign depends on direction)
177
Universal law of gravitation: F=?
G (m₁ m₂)/ r²
178
Orbital velocity for satellite near Earth: v=?
v= √(GM/r)
179
Torque formula τ=?
τ= r F sin(θ), or lever arm × force
180
Moment of inertia of a point mass about an axis: I=?
I= m r²
181
Rotational kinetic energy: K_rot=?
(1/2) I ω² (where I is moment of inertia, ω is angular velocity)
182
Angular momentum L for a point mass: L=?
L= I ω= m r² ω or r × p in vector form
183
Work-Energy Theorem: W_net=?
ΔK (change in kinetic energy)
184
Bernoulli’s Equation (ideal fluid): P + (1/2)ρv² + ρg h=?
constant along a streamline
185
Continuity equation (incompressible fluid): A v=?
constant (A is cross-section, v is fluid speed)
186
Ideal Gas Law: PV=?
n R T
187
Boyle’s Law (T constant): P₁V₁=?
P₂V₂
188
Charles’s Law (constant P): V₁/T₁=?
V₂/T₂
189
Thermodynamic work by gas at constant pressure: W=?
P (ΔV)
190
Heat Q needed to change temperature: Q=?
m c ΔT (c is specific heat)
191
Latent heat formula for phase change: Q=?
m L (L= latent heat)
192
Electrical power formula: P=?
P= I V= I²R= V²/R
193
Ohm’s Law: V=?
I R
194
Resistance in series: R_total=?
R₁+R₂+...
195
Resistance in parallel: 1/R_total=?
1/R₁ + 1/R₂ +...
196
Electric field from a point charge Q at distance r: E=?
kQ/r² (k=8.99×10⁹ N·m²/C²)
197
Electric potential from point charge Q at distance r: V=?
kQ/r
198
Capacitance of parallel-plate capacitor: C=?
ε₀ (A/d)
199
Energy stored in a capacitor: U=?
(1/2) C V²
200
Magnetic force on charge q with velocity v in field B: F=?
q v B sin(θ)
201
Faraday’s Law of Induction: EMF=?
− dΦ_B / dt (where Φ_B is magnetic flux)
202
A car accelerates from rest at 2 m/s². After 5 seconds, what is its speed?
v = v₀ + at = 0 + (2)(5)= 10 m/s.
203
An object falls freely (no air resistance). After 3 seconds, how far has it fallen from rest?
Use x= (1/2)gt² => (1/2)(9.8)(3²)= (4.9)(9)= 44.1 m (approx).
204
A box is pulled across frictionless ice with 20 N force, mass=10 kg. Acceleration?
F= ma => a= F/m= 20/10= 2 m/s².
205
A 2 kg mass has velocity from 2 m/s to 4 m/s. Change in momentum?
Δp= m(v₂ − v₁)=2(4−2)=4 kg·m/s.
206
A 3.0 kg object has velocity 4 m/s. What’s its kinetic energy?
KE= (1/2)mv²= (1/2)(3)(16)=24 J.
207
You lift a 5 kg object by 2 m. How much potential energy gained?
ΔPE= mgh= 5×9.8×2= 98 J (approx).
208
A 6 N horizontal force moves an object 3 m. Work done?
W= F d=6×3=18 J.
209
An object’s velocity changes from 10 m/s to 6 m/s in 2 s. Average acceleration?
a=Δv/Δt= (6−10)/2= −2 m/s².
210
A block slides on friction. No friction means KE+PE constant. If it starts with 100 J, how much energy after some motion?
Still 100 J (conservation of mechanical energy).
211
A projectile is launched horizontally at 5 m/s from height 20 m. Ignoring air, how long does it take to hit ground?
Use vertical free-fall: t= √(2h/g)= √(40/9.8)≈√4.08≈2.02 s.
212
With the same projectile: horizontal distance traveled in that 2.02 s if v_x=5 m/s?
Range= v_x× t= 5×2.02=10.1 m (approx).
213
Tug of war: if teams pull equally with 100 N each, net force on rope?
0 N (forces cancel).
214
On Earth, a 10 kg mass weighs how many newtons?
W= mg= (10)(9.8)= 98 N.
215
If you push with 15 N on a frictionless object, it pushes you back with 15 N. Which law?
Newton’s Third Law.
216
If friction coefficient is 0.2, normal force 50 N, friction force?
f= μ N=0.2×50=10 N.
217
A 2 kg block on frictionless slope (30° from horizontal). Acceleration down slope?
a= g sin(30°)= 9.8×0.5= 4.9 m/s².
218
A bullet of mass 0.01 kg traveling 200 m/s hits a wall, stops. Change in momentum?
Δp=0.01(0−200)= −2 kg·m/s (magnitude 2).
219
An object’s momentum is 8 kg·m/s, mass=2 kg, find velocity.
v= p/m= 8/2=4 m/s.
220
What is the net work done if an object speeds from KE=5 J to KE=15 J?
W= ΔKE=15−5=10 J.
221
A 3 kg mass rests on the floor, how much potential energy w.r.t. floor?
PE=0 J if reference is floor (none).
222
Force of 10 N applied at angle 60° from horizontal, displacement 5 m horizontally. Work done?
W= F cosθ × d=10 cos60° ×5= (10×0.5)×5=25 J.
223
A mass on spring (k=100 N/m) is stretched by 0.2 m. Potential energy stored?
PE= (1/2) k x²= 0.5×100×(0.2)²= (50)(0.04)=2 J.
224
Frictionless roller coaster starts at 20 m high. If speed at bottom is v, ignoring friction, mg(20)= (1/2)mv². Solve for v.
v= √(2gh)= √(2×9.8×20)= √392≈19.8 m/s.
225
An elevator lifts 500 kg up 10 m in 20 s. How much power used ignoring friction?
Power= (mgh)/t= (500×9.8×10)/20= (49000)/20=2450 W.
226
A wave has frequency 5 Hz, wavelength 2 m. Wave speed?
v= λ f= (2)(5)=10 m/s.
227
Period of a 5 Hz wave?
T=1/f=1/5=0.2 s.
228
Pendulum length is 1 m. Small angle period?
T=2π√(L/g)= 2π√(1/9.8)=2π√(0.102)= approx 2π×0.319=2.0 s.
229
A 500 g mass moves at 4 m/s. Kinetic energy?
KE= (1/2)(0.5)(4²)= (0.25)(16)=4 J.
230
Capacitor of 10 µF at 12 V. Energy stored?
U= (1/2)CV²=0.5×(10×10⁻⁶)×(12²)= (5×10⁻⁶)×144=7.2×10⁻⁴ J.
231
Electric circuit with V=9 V, R=3 Ω. Current I=?
I= V/R=9/3=3 A.
232
Sound wave of speed 340 m/s, frequency 170 Hz. Wavelength?
λ= v/f= 340/170=2 m.
233
A force of 10 N acts on mass 2 kg for 2 s. Impulse J=?
J= F×t=10×2=20 N·s => Δp=20 kg·m/s.
234
If object’s momentum changes by 20 kg·m/s, mass=4 kg, velocity change?
Δv= Δp/m=20/4=5 m/s.
235
Falling from rest for 2 s, ignoring air, velocity?
v= gt= (9.8)(2)=19.6 m/s.
236
Projectile’s horizontal velocity if launched at 10 m/s, angle=0°, ignoring air?
Constant 10 m/s horizontally.
237
If friction is 5 N, distance=4 m, friction does how much negative work?
W= −F d= −(5)(4)=−20 J.
238
Current 2 A flows 10 s, total charge passed?
Q=I t= (2)(10)=20 C.
239
Parallel-plate capacitor, area=1 m², separation=0.01 m, ignoring dielectric. Capacitance?
C= ε₀(A/d)= (8.85×10⁻¹²)(1)/(0.01)=8.85×10⁻¹⁰ F.
240
Ohm’s Law: if R=4 Ω, and I=2 A, voltage needed?
V= IR= (2)(4)=8 V.
241
Ball on string, radius=1 m, speed=3 m/s. Centripetal acceleration?
a_c= v²/r= (3²)/1=9 m/s².
242
Energy to raise 1 kg water by 10°C. Specific heat c= 4184 J/kg·K => Q=?
Q= m c ΔT= (1)(4184)(10)= 41840 J.
243
Magnetic force on 2 C charge moving at 3 m/s in B= 1 T, velocity perpendicular => F=?
F= q v B= (2)(3)(1)=6 N.
244
Two 2 Ω resistors in series => total R=?
4 Ω.
245
Same two 2 Ω resistors in parallel => total R=?
1/(1/2+1/2)=1 Ω.
246
Light speed c=3×10⁸ m/s, frequency 6×10¹⁴ Hz => wavelength?
λ= c/f= (3×10⁸)/(6×10¹⁴)= 5×10⁻⁷ m (500 nm).
247
Sine wave amplitude 2 cm, frequency 10 Hz => period?
T=1/f=1/10=0.1 s.
248
Boyle’s Law: if P₁= 2 atm, V₁=2 L, new volume if pressure becomes 4 atm (constant T)?
P₁V₁= P₂V₂ => 2×2=4×V₂ => V₂=1 L.
249
Gravitational potential near Earth: U=mgh => if mass=10 kg, h=3 m => U=?
U= (10)(9.8)(3)=294 J.
250
An object at rest has momentum p=?
p=0 kg·m/s.
251
If mechanical advantage of a lever is 4, applying 10 N force => output?
40 N (ideally, ignoring friction).
