9 Force and Momentum

Question 1

what is momentum?

Answer 1

an objects mass x its velocity

Question 2

How is Newton’s 1st law of motion related to its momentum?

Answer 2

If an object’s force and mass are constant then its momentum must also be constant

Question 3

How can you re-write Newton’s 2nd law of motion?

Answer 3

the rate of change of momentum of an object is proportional to the resultant force on it.
== the resultant force is proportional to the change in momentum per second

Question 4

what does the area under a force time graph represent?

Answer 4

the change of momentum or impulse

Question 5

what is the change in momentum of an object hitting a wall normally?

Answer 5

its direction is reversed
so, change in momentum = (-mv) - (mu)

Question 6

what is the change in momentum of an object hitting the wall at an angle?

Answer 6

only the normal components are used.
so, change in momentum = (-mv cos x) - (mu cos x)
x = angle
v = final velocity
u = initial velocity

Question 7

what does the principle of conservation of momentum state?

Answer 7

for a system of interacting objects, the total momentum remains constant, provided no external resultant force acts on the system
total final momentum = total initial momentum

Question 8

what equation can be derived from the principle of the conservation of momentum?

Answer 8

MV + mv = MU +mu

Question 9

what is an elastic collision?

Answer 9

where there is no loss of kinetic energy

Question 10

what is an inelastic collision?

Answer 10

it occurs when the colliding objects have less kinetic energy after the collision than before the collision