Question

What impulse is exerted in each of the following cases?
The Earth pulling down on a 12kg rock during the 3.0 seconds it takes to fall down from a cliff

A billiard ball of mass 200 g rolls towards the right hand cushion of a billiard table at 2.0m/s and rebounds straight back at 2.0m/s.
(a) What is its change in momentum as a result of hitting the cushion.

(b) what impulse is given to the ball by the cushion

Please help, will give medals out but I'm so confused by this completely.

Answer 1

Impulse is the same as momentum; impulse or pulse is a sudden increaseof a quantity followed by a decrease then it comes another increase, occuring alternatively, just like the heart beat reading in that machine.

Answer 2

So pulse is Ft, where F is force and t time. Or mv, where m is mass and v is velocity.
We can use Ft, because we can find F and we have t.
F is mg or 12*9.81. And t is 3seconds.
Hence, we ultimately have Ft or 12*9.81*3=?

Answer 3

Impulse is the change of momentum or Force over a period of time.

Answer 4

If a rock of 12 kg falls from a cliff for 3s, the impulse is 12*9.8*3=352.8

Answer 5

impulse is like 'change in force in a short period of time'

so, for an impulse like take 'Im' = F * t (force * time)

and can also be written as im = m * v (mass * Velocity) which is also momentum = M

therefore: a) momentum = m * v
( here v is not 2.0 m/sec. since, it is difference in velocity, i.e., v1-v2 = 2.0 - 2.0 = 0)

so, momentum = 200 * 0 = 0
hence, no change in momentum...

and for the rock question... the first guy's answer deserve a medal...

Keep Asking & Answering...

Answer 6

Thanks.