Sand from a stationary hopper falls on a moving conveyor belt at the rate of 5.70 kg/s. The convey or belt is supported by frictionless rollers and moves at a constant speed of v = 0.690 m/s under the action of a constant horizontal external force Fext supplied by the motor that drives the belt.
(a) Determine the sand rate of change of momentum in the horizontal direction.
N
(b) Determine the force of friction exerted by belt on sand.
N
(c) Determine the external force Fext.
N
(d) Determine the work done by Fext in 1 second.
J
(e) Determine the kinetic energy acquired by the falling sand each second due to the change in its horizontal motion.
J
(f) Describe why are the answers to parts (d) and (e) different?