Explain how to find the work done in moving an object along a line in the direction of a constant force.

Solution 3E Step1 If an object is moving in a straight line with position function s(t), then the force F on the object at time t is the product of the mass of the object times its acceleration. d s F = m dt Step2 Note if velocity and acceleration have opposite signs, the force is acting in the direction opposite to the movement of the object. In the SI metric system, mass is measured in Kilograms (kg), displacement in meters (m) and the time is measured in seconds (s). The force is measured in Newtons; N = kg·m/s2 . A force of one Newton acting on a mass of 1 kg produces an acceleration of 1 m/s2 . In the British system the unit of force is a pound (lb). Step3 When a body moves a distance d along a straight line as a result of being acted on by a force of constant magnitude F, we define the work done by the force on the body with the formula; work = force × distance, W = F d. Note Forces applied in the direction of motion have positive values in this calculation and forces applied in a direction opposite to the direction of motion have negative values.