Problem
The work done by a force as it acts on an object equals the force times the displacement times the cosine of the angle between the force and displacement vectors.
a) Calculate the work you do if you apply a horizontal force of 220 N to a box and it moves forward by 11 m.
You need to lift a 40 kg box up 1.5 m to put it in a moving van.
a) How much force do you need to apply if you lift the box straight up at constant velocity?
b) How much work do you do in lifting the box into the van?
c) Calculate the force you must apply to the box if you push it up a 10° ramp. How does this compare to the force from a)?
d) Calculate the work done in pushing the box up the ramp to the van. How does this compare to the work from b)?
You throw a baseball by applying a force of 300 N to the ball over a horizontal distance of 1 m in the direction of the displacement. The ball has a mass of 145 g.
a) How much work do you do to the ball?
b) Using the Work-Kinetic Energy Theorem, find the final speed of the ball as it leaves your hand. What is this in miles per hour?