Question

The body weighing 40 kg slides across the sloping plane 4 m long, forming a 45 ° angle with the horizon. Find the work done by the force of gravity on the body during its displacement across the inclined plane.

Answer 1

We can find the work done by the force of gravity on the body from the formula:

$$W_g=mgh.$$

We can find $h$ from the geometry:

$$sin\theta=\dfrac{h}{d},$$ $$h=dsin\theta.$$

Finally, we can calculate the work done by the force of gravity on the body:

$$W_g=mgdsin\theta=40\ kg\cdot9.8\ \dfrac{m}{s^2}\cdot4.0\ m\cdot sin45^{\circ}=1109\ J.$$