Question

A person is pushing a car down a horizontal road. She exerts a force of 4000 N at an angle of 10°. If the total mass of the car is 1000 kg and the µ between the car and the road is -0.35, how much work is done if the car travels 100 meters?

Answer 1

$$W=W_{push}-W_{fr},$$ $$W=F_{push}dcos\theta-\mu mgd,$$ $$W=4000\ N\cdot100\ m\cdot cos10^{\circ}-0.35\cdot1000\ kg\cdot9.8\ \dfrac{m}{s^2}\cdot100\ m,$$ $$W=50923\ J.$$