Question

CONFUSED!!!

Answer 1

A. Impulse is simply the product of Force and time. Therefore,

I = F * t                                 ---> 1

where I is impulse, F is force, t is time

 

However another formula for solving impulse is:

I = m vf – m vi                    ---> 2

where m is mass, vf is final velocity and vi is initial velocity

 

Therefore using equation 2 to solve for impulse I:

I = 2000kg (0) – 2000kg (77 m/s)
I = -154,000 kg m/s

 

B. By conservation of momentum, we also know that Impulse is conserved. That means that increasing the time by a factor of 3 would still result in an impuse of -154,000 kg m/s. So,

I = F’ * (3 t) = -154,000 kg m/s

Since t is multiplied by 3, therefore this only means that Force is decreased by a factor of 3 to keep the impulse constant, therefore:

(F/3) (3t) = -154,000 kg m/s

 

 

Summary of Answers:

A. I = -154,000 kg m/s

B. Force is decreased by factor of 3