Question

At one instant, a 19.0-kg sled is moving over a horizontal surface of snow at 4.50 m/s. After 7.80 s has elapsed, the sled stops. Use a momentum approach to find the magnitude of the average friction force acting on the sled while it was moving.

Answer 1

Frictional force, F = -10.96 N

Step-by-step explanation:

It is given that,

Mass of the sled, m = 19 kg

Initial velocity of the sled, u = 4.5 m/s

After 7.80 s has elapsed, the sled stops. We need to find the magnitude of the average friction force acting on the sled while it was moving. The change in momentum is equal to the impulse imparted i.e.

`F.\Delta t=m(v-u)`

`F=(m(v-u))/(\Delta t)`

`F=(19\ kg(0-4.5\ m/s))/(7.8\ s)`

F = -10.96 N

So, the average frictional force acting on the sled is 10.96 N. Hence, this is the required solution.