Answer:
The work done on the box is 69.28 ft-lb
Step-by-step explanation:
Work done = force × height
Force (F) = 10 pounds
The height (h) is calculated using trigonometric ratio
Length of ramp (hypotenuse side) = 8 feet
Angle of inclination above the horizontal = 30°
h/8 = cos 30°
h = 8cos 30° = 8×0.8660 = 6.928 feet
Work done = F×h = 10 pounds × 6.928 feet = 69.28 ft-lb