Question

A 4lb force acting in the direction of (4,-2) moves an object just over 7 ft from the point (0,4) to (5,-1). Find the work done to move the object to the nearest foot-pound

a)35 ft:lbs
b)27 ft:lbs
c)18 ft:lbs
d)7ft:lbs

Answer 1

The work done has the formula
W = F d
where the force and the displacement have the same direction
We can determine displacement using the distance formula
d = √[(5 - 0)² + (-1 - 4)²]
d = 5√2

Next, the force along the direction of the displacement must be determined
Use trigonometry to determine the angle θ

Finally, the work is calculated using the formula
W = F d / cos θ
substitute the values to get the answer