Momentum

Question 1

Definition of momentum with unit

Answer 1

mass, m, of an object multiplied by its velocity, v (kgms-1 or Ns)

Question 2

Is momentum scalar or vector

Answer 2

Vector

Question 3

The Principle of the Conservation of Momentum states that

Answer 3

if objects collide, the total momentum before the collision is the same as the total momentum after the collision (provided that no external forces - for example, friction - act on the system).

Question 4

Change of momentum when a particle of mass M and initial velocity u hits a wall and bounces back

Answer 4

Final momentum - inital momentum = -mu - (mu) = -2mu

Question 5

Force can be defined as the

Answer 5

rate of change of momentum (mv-mu/t)

Question 6

3 types of collisions and details of each

Answer 6

Perfectly elastic: momentum and kinetic energy is conserved, e=1 so relative speed of approach=relative speed of separation

Inelastic: momentum conserved, kinetic energy not conserved, e varies

Perfectly inelastic, momentum conserved, kinetic energy not conserved, relative speed of separation = e = 0 so the objects stick together after collision

Question 7

Impulse = units

Answer 7

change in momentum = force*time (Ns or Kgm/s)

Question 8

How cars have adapted using momentum and impulse

Answer 8

they have crumple zones which make the collisions last longer. A longer time means that you can achieve the same change in momentum during a collision by applying a smaller force. And it is the force that hurts the passengers.

Question 9

Impulse from force (y) time (x) graph

Answer 9

Impulse = change in momentum = area under force-time graph