Question

When an object slides down an inclined plane, the angle between the displacement and the force of gravity is the same as the angle that the surface makes with the horizontal. Suppose you have a 2-kg cart rolling a distance of 1.5 m down a 30° incline. According to Eq. (7.8), what is the work done on it by the force of gravity? Select One of the Following:

(a) 3J
(b) 25.5 J
(c) 2.6J
(d) 14.7 J

Answer 1

Answer:

(d) 14.7 J.

Explanation:

Using the equation,

W = mghsin∅.................  equation 1

Where W = work  done on  the cart by the force of gravity, g = acceleration due to gravity, h = height, ∅ = angle between the displacement and the force of gravity.

Given: m = 2 kg, g = 9.8 m/s², h = 1.5 m, ∅ = 30°

Substitute into equation 1

W = 2(9.8)(1.5)sin30

W = 2×9.8×1.5×0.5

W = 14.7 J.

The right option is (d) 14.7 J