Question

Question: At one instant, a 17.5-kg sled is moving over a horizontal surface of snow at 3.50 m/s. After 8.75 s has elapsed, the sled stops. Use a momentum approach to find the average friction force acting on the sled while it was moving.


Please check my work. If it is incorrect please provide detail.
Sled mass (m) = 17.5kg moving over a horizontal surface
initial velocity of (U) = 3.5 m/s
Initial momentum of the sledge
(P₁)=mU
(P₁)=(17.5kg)(3.50 m/s)
= 61.25 m/s
Sled stops at (t) = 8.75s
final velocity (V)=0
Initial momentum of the sled
(P₂) =0
Newtons 2nd Law of Motion
F=∆P/∆t
= (P₁-P₂)/t
= (0-61.25 m/s)/8.75s
=7 m /s

This is the average friction force (F) acting on the sled while it was moving.

Answer 1

Yes , your answer is correct < --