Physics 10 Flashcards
What are scalar quanties?
- Magnitude (number) only
- time, distance, speed, energy, mass
What are vector quantites?
- Magnitude (number) and a direction
- displacement, velocity, acceleration, force
What is the symbol for distance?
d
What is the symbol for displacement?
s
What is the symbol for velocity (speed)?
v
How do you convert m/s to km/h?
multiply by 3.6
How do you convert km/h to m/s?
divide by 3.6
What is uniform velocity/speed?
The magnitude and direction of the velocity/speed stays constant
What is instantaneous speed?
The speed at a particular moment in time
What is average velocity/speed?
The total displacement over the total time
If speed is uniform, what is the instantaneous speed?
The same as the average speed
How do you calculate acceleration?
(final velocity - initial velocity) divided by total time
What is acceleration?
The rate of change of velocity
What is the symbol for inital velocity?
u
What is the symbol for final velocity?
v
How do you solve a SUVAT question?
- work out which variables you have/don’t have/need
- work out which equation to use
- substitute letters for numbers
- solve
Is the initial direction always positive or negative?
positive
What is the acceleration of Earth gravity?
9.8m/s²
What is magnitude?
A number NOT a direction
What is a force?
An interaction that can:
* change the velocity of an object
* cause a distortion in the size or shape of an object
* cause a rotation about an axis
What are examples of field forces?
- gravitational
- magnetic
- electrostatic
What are examples of contact forces?
- applied force
- tension
- friction
- normal force
What is tension?
The force experienced in a taut string/rope (stretch)
What is friction?
Force that opposes motion of an object, parallel to motion/direction
What is normal force?
Perpendicular force exerted by the surface of an object in contact with it
What is the SI unit for force?
N (newtons)
What is resultant/net force?
Single vector that has the same effect as the individual forces acting together
When does an equilibrium happen?
When the resultant force is zero
What is the SI unit for mass?
kg
What is the SI unit for weight?
N (netwons)
What is the formula for force?
F = ma
What are Newton’s three laws of motion?
- An object in motion/rest stays in motion/rest, unless acted on by an outside, net force (inertia)
- F = ma
- For every action there is an equal and opposite reaction
Describe Newton’s second law of motion
- For a constant mass: the larger the force, the larger the acceleration
- For a constant acceleration: The larger the mass, the larger the force needed
Describe Newton’s first law of motion
- An object in motion/rest stays in motion/rest, unless acted on by an outside, net force
- The outside force = net force
- also called inertia
Where there is a force, there is…
acceleration
Where there is no acceleration, there is no…
resultant force
What is drag?
- A force that opposes the motion of objects through a gas or liquid
- increases rapidly with speed and gets larger when the surface area of the object is increased
Describe Newton’s third law of motion
- Proves normal force
- When on flat ground, the normal force is in equilibrium with the weight
- When on an incline going down, the normal force is no longer in equilibrium with the weight
How would you calculate the force of A on B?
Force = mass of B * acceleration
What is the formula for the net force when there is friction?
Net force = Applied force - Frictional force
Describe tension in a rope
The tension is always equal at both ends of the rope
What is the difference between static and kinetic friction?
- static friction is the force of friction on an object that is not moving
- kinetic friction is the force of friction on an object that is moving
- kinetic friction is nearly constant with speed
- Kinetic friction is usually significantly smaller than static friction
What is inertial mass?
Measures an object’s resistance to being accelerated by a force (motion) - not due to gravity
What is gravitational mass?
The mass of a body determined by its response to the force of gravity
How do you calculate applied force when on a slope?
Applied force = mg * sin(angle of slope)
How much time is in between ticker tape dots?
0.02s
How do you work out if ticker tape is accelerating?
The more spaced out the dots are, the faster the object is moving
When an object is stationary, the applied force and static friction are…
oppposites (equal to zero)
How do you calculate instantaneous velocity?
(future velocity - past velocity) divided by (future time - past time)
What is work?
When a force causes a particle or object to move
What is the SI unit for work/energy?
J (Joules)
What is the equation for work?
W = Force x displacement
How do you calculate work when the force is applied at an angle?
W = F * cos(angle of force) * displacement
What is the final velocity for an object dropped from a height?
v = √2gh
What is the work-energy theorem?
Net work = total KE
How do you calculate acceleration from a velocity - time graph?
rise / run
How do you calculate displacement from a velocity - time graph?
total area underneath the line
How do you calculate velocity from a displacement - time graph?
rise / run
How do you calculate acceleration from a displacement - time graph?
(current velocity - inital velocity) divided by time bewteen the two points
What is the velocity of this graph?
0 - standing still
What is the velocity of this graph?
Constant velocity
What is the acceleration of this graph?
Constant acceleration
What is the acceleration of this graph?
Constant deceleration
What is the formula for net force for an object including tension?
F = T + mg
What is the formula for initial mechanical energy?
initial ME = initial GPE + initial KE
What is the formula for final mechanical energy?
final ME = final GPE + final KE
What is the formula for final and initial mechanical energy?
initial ME = final ME
What is the formula for final and initial mechanical energy?
initial ME = final ME
What is the formula for weight?
W = mg
In an elevator, when there is no acceleration, the tension and weight are…
opposites (equilibrium)
Where there is constant velocity, there is no…
acceleration
What is velocity?
The rate of change of displacement
What is the difference between speed and velocity?
- speed is a magnitude, velocity is a magnitude and direction
- speed is distance/time
- velocity is displacement/time
Assuming no energy is lost, the formula for Kinetic Energy and Potential energy is…
KE = PE
What are types of potential energy?
- gravitational
- magnetic
- elastic
What is the formula for net force in a pulley system?
Net Force = (m₁+m₂)a
What is the formula for theoretical force in a pulley system?
Theoretical force = m₂g
What is the formula for theoretical and net force in a pulley system?
(m₁+m₂)a = m₂g
How do you find the percentage difference between the theoretical and net force in a pulley system?
[(Theoretical force - Net force) divided by theoretical force] times 100