Author Question: What is the minimum work that a motor must do to lift a 70 lb object from the floor to a height of ... (Read 97 times)

ec501234 · **on:** Jul 28, 2018

What is the minimum work that a motor must do to lift a 70 lb object from the floor to a height of 14 feet?
a. 5 b. 70 c. 700 d. 980 e. 2010 ft-lbs

Question 2

A rock is thrown from the edge of the top of a 100-ft tall building at some unknown angle above the horizontal. The rock strikes the ground a horizontal distance of 160 ft from the base of the building 5.0 s after being thrown. Assume that the ground is level and that the side of the building is vertical. Determine the speed with which the rock was thrown.
a. 72 ft/s
b. 77 ft/s
c. 68 ft/s
d. 82 ft/s
e. 87 ft/s