Skateboarder with a mass of 150kg

[roske]

A skateboarder with a mass of 150 kg is traveling at a final velocity of 13m/s and collides with a steel dumpster. The dumpster does not move. The skateboarder comes to a stop at 0.25 seconds. What is his rate of acceleration as he stops? How much force does he exert on the dumpster?

Can someone help me please.

 

[JesseC]

Can you write down an equation for the relationship between time, acceleration and change in velocity?

 

[roske]

Initial velocity= 13ms^-1
Final velocity= 0ms^-1
Time= 0.25s

A) Rate of acceleration = (V-U)/T = (0-13)/0.25 = -52ms^-2

B) Force exerted on the dumpster= F= (MV)/ T = (150*13)/0.25 = 7800N

I think?

 

[JesseC]

That looks correct to me! Average acceleration is change in velocity divided by change in time. Force exerted is equal to the change in momentum.