Question

A 128 N carton is pulled up a frictionless baggage ramp inclined at 30.0 ∘ above the horizontal by a rope exerting a 72.0 N pull parallel to the ramp's surface. If the carton travels 5.20 m along the surface of the ramp, calculate the work done on it by the rope, gravity, and the normal force of the ramp.

What is the net work done on the carton?

Answer 1

Work done by rope = force exrted by rope * distance moved along the ramp = 72*5.2=374.4 J

work done by gravity = weight of carton*vertical distance travelled = 128*(-5.2*sin30)=-332.8 J

The work done by gravity is negative because the carton is moving upwards whereas gravitaional force is scting downwards

The work done by normal force of the ram on the carton is zero. this is because the normal force on ramp and the moveemtn of carton are perpendicular to each other.

Net work done on the ramp = 374.4+332.8=707.2 J