Question

Starting from rest Maria pulls horizontally on her new wagon for 1.1 seconds. She exerts a constant force of 89N against a frictional force of 43N. The wagon's final velocity is 3.2m/s. If she is on a level ground, how much does the wagon weigh?

Answer 1

Fnet= m a= m *3.2/1.1
89-43=m * 3.2/1.1 solve for m
weight= mg

Answer 2

Use the fact that impulse
= (net force)*(time) = (momentum change)

The momentum given to the wagon is
(89 - 43)* 1.1 = 50.5 kg m/s

Divide that by the final velocity to get the mass in kg.