3.4.1.6 Momentum

Question 1

What is momentum?

Answer 1

Momentum is the product of mass and velocity.

Question 2

What is linear momentum?

Answer 2

Linear momentum is momentum in a straight line.

Question 3

What is the equation for momentum?

Answer 3

Momentum = mass x velocity.

Question 4

Is momentum a scalar or vector?

Answer 4

Momentum is a vector quantity, so has size and direction.

Question 5

What is the unit for momentum?

Answer 5

Momentum = kgm/s.

Question 6

What is the condition for momentum to be conserved?

Answer 6

Assuming no external forces act, momentum is always conserved. This means the total momentum of two objects before they collide equals the total momentum after the collision.

Question 7

What are the 2 two types of collisions?

Answer 7

Elastic Collisions

Inelastic Collisions

Question 8

What is an elastic collision?

Answer 8

An elastic collision is one where momentum is conserved and kinetic energy is conserved. No energy is dissipated as heat or sound.

The two objects bounce off each other.

Question 9

What is an inelastic collision?

Answer 9

An inelastic collision is when some of the kinetic energy is converted into other forms during the collision. The momentum is still conserved.

The two objects join together and their mass combines.

Question 10

What is Newtons Second Law?

Answer 10

Newtons 2nd law states that force is the rate of change of momentum.

The rate of change of momentum of an object is directly proportional to the resultant force which acts on the object.

Question 11

What is the equation for the rate of change of momentum?

Answer 11

Force = Change in Momentum / Change in Time.

Question 12

What is impulse?

Answer 12

Impulse is the change of momentum.

It is equal to force x time.

Question 13

What is the unit for impulse?

Answer 13

Newton-seconds.

Question 14

What does the area of a force - time graph?

Answer 14

Change in momentum.

Question 15

How can the force of an impact be reduced?

Answer 15

By increasing the impact time.

Question 16

What do crumple zones do?

Answer 16

Crumple zones are the parts at the front and back of the car that crumple up on impact.
This causes the car to take longer to stop, increasing the impact time and decreasing the force on the passengers.

Question 17

What do seat belts do?

Answer 17

Seat belts will stretch slightly, increasing the time taken for the wearer to stop.
This reduces the forces acting on the chest.

Question 18

What do air bags do?

Answer 18

These slow down passengers more gradually, and prevent them from hitting hard surfaces inside the car.