A sled is at rest on a horizontal field. The sled has a mass of 21.6kg. A man exerts a horizontal force of 49.7N on the sled. As soon as the sled starts to move, a friction force of 13.8N acts on the sled.

a. What is the acceleration of the sled while the man is pushing the sled?
b. What is the acceleration of the sled just after the man stops pushing it?

1 answer

F = 49.7 - 13.8 = 21.6 a
so
a = (449.7-13.8)/21.6

F = -13.8
a = - 13.8/21.6