A 100-N force has a horizontal component of 80 N and a vertical component of 60 N.The force is exerted to a cart on a level frictionless floor.The cart starts from rest and moves 2.0 m horizontally along the floor due to this force.What is the cart's final kinetic energy?
A)200 J
B)160 J
C)120 J
D)zero

Question

Quizplus · Accepted Answer

The horizontal component of the force causes the cart to move 2.0 m horizontally along the floor, while the vertical component does not affect the motion since the cart is on a level surface. Therefore, we can ignore the vertical component and only consider the horizontal component of the force.

Using the formula for work, W = Fd cos(theta), where F is the horizontal component of the force, d is the distance the cart moves horizontally, and theta is the angle between the force and the horizontal (which is 0 degrees in this case):

W = (80 N)(2.0 m)cos(0 degrees) 
W = 160 J

Since the cart starts from rest, its initial kinetic energy is zero. Therefore, the final kinetic energy of the cart is equal to the work done on it by the 100-N force, which is 160 J.

A 100-N Force Has a Horizontal Component of 80 N