Question

Find the work done by a force of 4 pounds acting in the direction of 41° to the horizontal in moving an object 5 feet from (0, 0) to (5, 0).

A. 13.1 ft-lb
B. 16.2 ft-lb
C. 15.1 ft-lb
D. 30.2 ft-lb

Answer 1

Do you know the formula for work? It is the dot product of the net force on the object and the angle

Answer 2

no i don't

Answer 3

Then you won't be able to do this problem. But yea, W = F*d*cos(theta)

Answer 4

will you show me how

Answer 5

Just plug the numbers into the formula:

Work = 4*5*cos(41 deg)

You have to use a calculator unless you know cos(41) off the top of your head.

Answer 6

cos41 equals -0.9873..etc
this can't be right?

Answer 7

Yea, your calculator is in radian mode. You need to use degrees. Or convert 41 degrees to radians.

Answer 8

thank you, i got it now.