Dynamics

Question 1

Dynamics

Answer 1

The branch of physics that deals with the study of forces and their effects on the motion of objects.

Question 2

Mass

Answer 2

The measure of an amount of matter in an object

Question 3

Weight

Answer 3

-The effect of a gravitational field on a mass,
-The product of the mass times the force of gravity
-W = mg
m =mass
g = acceleration due to gravity 9.81m/s^2
-Measured in Newtons (N)

Question 4

Free Fall

Answer 4

An object under free fall is falling solely under the influence of gravity

Question 5

Mass v Weight

Answer 5

An object’s mass always remains the same, however, its weight will differ depending on the strength of the gravitational field

Question 6

Newtons First Law of Motion (Principle of Inertia)

Answer 6

Bodies remain in motion or at rest unless acted upon by an external force

Question 7

Inertia

Answer 7

The reluctance of a body to start moving once at rest or stop moving once in motion

Question 8

Newtons Second Law of Motion

Answer 8

The rate of change of momentum is directly proportional to the magnitude of the applied force producing it and takes place in the reaction of the applied force

F ∝ m(v-u), a = v-u
t t
F = ma

Question 9

Newtons Third Law of Motion

Answer 9

For every action, there is an equal and opposite reaction

Question 10

Force

Answer 10

The external cause that changes or tends to change the state of the body once applied
F = ma
-Vector Quantity
-Units:kg⋅m/s⁻²
-Dimensions:[MLT⁻²]

Question 11

Contact Force

Answer 11

A force which is applied by actually touching the body

Question 12

Tension Force (T)

Answer 12

A force is applied to the cable, rope, or string at the ends. It is directed towards the length of the wire and pulls the energy equally from both ends (contact force)
T = mg + ma
T: Tension
m: Mass
g: Gravitational force (9.8m/s⁻²)

Question 13

Spring Force (Restoring Force)

Answer 13

If any force acts on the body that will either compress or stretch the body, then this force acts to restore the equilibrium.(contact force)
F =kx
F: Spring Force
k: Spring Constant
x: Distance stretched or compressed

Question 14

Normal Force

Answer 14

Force is exerted by a surface that is perpendicular (normal) to the surface and supports the weight of an object resting on it. It prevents the object from “falling” through the surface. (Contact Force)
FN​=mgcos(θ)
​θ: Angle of the incline,
𝐹: Normal Force,
𝑚: Mass of the object,
𝑔: Acceleration due to gravity.

Question 15

Frictional Force

Answer 15

The opposing force generated when two surfaces are in contact or slide opposite of each other. (Contact Force)

Question 16

Static Friction

Answer 16

-This is the friction that resists the initiation of motion between two surfaces.
-It acts when an object is at rest relative to the surface.
-The static friction force adjusts itself to match the applied force, up to a maximum limit, beyond which motion occurs
Fstatic max​=μs​N

μs​: Coefficient of static friction
N: Normal force

Question 17

Kinetic (or Dynamic) Friction:

Answer 17

This is the friction that opposes the motion of an object that is already sliding over a surface.
Fk​=μk​N
μk​: Coefficient of kinetic friction
N: Normal force

Question 18

Non-Contact Force

Answer 18

The force that acts without any physical contact between the bodies.

Question 19

Gravitational Force

Answer 19

The force which acts between the two bodies having some mass. (Non-contact Force)
-An attractive force never repulsive

Question 20

Electrostatic Force

Answer 20

The force that acts between two charged bodies

Question 21

Linear Momentum (p)

Answer 21

The product of the mass and velocity. (Vector Quantity)
p = mv
p: Linear Momentum
m: Mass in kg
v: Velocity

Question 22

Conservation of Linear Momentum

Answer 22

When two or more bodies collide, the total momentum of the system is conserved provided there is no external force on the system

F1 =m1(v1 - u1), F2 =m2(v2 - u2)
( t ) ( t )
F1 = -F2
m1(v1 - u1) -m2(v2 - u2)
( t ) ( t )
m1v1 + m2v2 = m1u1 +m2u2

Question 23

Elastic/Perfectly Elastic Collision

Answer 23

-Kinetic energy is conserved
-Linear momentum is conserved
-Bodies separate after collision
Ex: Collision of gas molecules

Question 24

Inelastic Collison

Answer 24

-Kinetic energy is not conserved
-Linear momentum is conserved
-Bodies separate after collision
Ex: Ball bouncing on a concrete floor

Question 25

Perfectly Inelastic Collision

Answer 25

-Kinetic energy is not conserved
-Linear momentum is conserved
-Bodies stick together and move with a common velocity after collision
Ex: A trailer colliding with a saloon car

Question 26

External and Internal Forces

Answer 26

External Forces: Forces that act on structure from the outside
Ex: Friction, Weight, etc.

Internal Forces: Forces exchanged by the particles in a system
Ex: Tension in a string

Question 27

Kinetic Energy of an Elastic Collision

Question 28

Kinetic Energy of an Inelastic Collision