A girl pulls a 1.7 kg cart across a level floor causing it to accelerate at 1.9 m/s^2. If the force of friction between the wheels and the cart is 5.4 N, what is the force applied by the girl?

Answer 1

The girl must overcome the frictional force by an amount necessary to produce the stated acceleration. The overall force on the cart is F = ma. Therefore we can state that

F_total = F_girl - F_friction, or in terms of F_girl,

F_girl = F_total + F_friction, or

F_girl = ma + F_friction

Substitute in values:

F_girl = (1.7Kg)(1.9m/s²) + 5.4N

= 8.6N