1.3 Dynamics

Question 1

What are Newton’s 3 laws of motion?

Answer 1

1. An object’s velocity will remain constant unless acted upon by a resultant force
2. The rate of change of momentum of a body is directly proportional to the resultant force acting on it (F = ma)
3. If body A exerts a force on body B, body B will exert an equal and opposite force on body A

Question 2

What is the definition of momentum?

Answer 2

p = mv, the product of mass and velocity

Question 3

Define elastic and inelastic collisions

Answer 3

Elastic - kinetic energy is conserved during a collision
Inelastic - kinetic energy is lost during a collision

Question 4

What are the conditions for Newton’s 3rd law?

Answer 4

• The force exerted by each body acts on the other, not the same one
• The forces must be the same kind of force

Question 5

Define normal force

Answer 5

The force acting at a normal to the surface on which the body rests as a result of its weight

Question 6

Give 3 examples of contact forces

Answer 6

• Normal force
• Air resistance
• Friction