Dynamics

Question 1

What is newton’s first law of motion?

Answer 1

Newton’s first law of motion states that a body will remain in its state of rest or uniform motion in a straight line unless acted upon by a resultant force

- Implies that all matter has inertia which the property of a body that resists change in motion
- Mass is a measure of inertia of the body. The more mass a body has, the greater is its inertia and the harder it is to change its state of motion

Question 2

What is newton’s second law of motion?

Answer 2

Newton’s second law of motion states that the rate of change of momentum of a body is directly proportional to the resultant force acting on it and the change takes place in the direction of the resultant force

Question 3

What is momentum

Answer 3

p = mv

Question 4

What is resultant force

Answer 4

-Resultant force is the rate of change of momentum
-For a body of constant mass
F α dp/dt
F α d(mv)/dt
F α mdv/dt
F α ma
F = kma

Question 5

What is the definition of a newton

Answer 5

1 newton is defined as the force which when acting on a 1 kg mass, produces an acceleration of 1 ms^-2

Question 6

What is impulse

Answer 6

Impulse is the product of the force acting on a body and the time interval during which the force is exerted

Question 7

What is the formula for impulse

Answer 7

impulse = FΔt

Question 8

What is represented by the area under a force - time graph

Answer 8

impulse

Question 9

What is a change in momentum

Answer 9

impulse

Question 10

What is the rate of change of momentum

Answer 10

force

Question 11

What is newton’s third law of motion

Answer 11

Newton’s third law of motion states that if a body A exerts a force on body B, then body B exerts an equal and opposite force on body A

Question 12

What is the principle of conservation of momentum?

Answer 12

The principle of conservation of momentum states that the momentum of a system of objects remains constant if no resultant external force acts on the system

Question 13

What are elastic collisions

Answer 13

• Both momentum and kinetic energy is conserved

- Relative velocity of separation = relative velocity of approach

Question 14

What are inelastic collisions?

Answer 14

Momentum is conserved but kinetic energy is not

Question 15

What are completely inelastic collisions?

Answer 15

Momentum is conserved and the particles stick together after collision so that their final velocities are the same