Problem 2E

Problem

Unless otherwise stated, in the following problems we assume that the gravitational force is constant with g = 9.81 m/sec2 in the MKS system and g = 32 ft/sec2 in the U.S. Customary System.

A 400-lb object is released from rest 500 ft above the ground and allowed to fall under the influence of gravity. Assuming that the force in pounds due to air resistance is -10y, where v is the velocity of the object in ft/sec, determine the equation of motion of the object. When will the object hit the ground?

Solution:

Step 1:

In this problem,we have to find the time when the object hit the ground.