Name: ________________
Period: ___
Chapter 4 Work & Energy
1. Suppose you live in the Penthouse Apartment on the top floor
of the Hotel Ponchatrain in Detroit, 145m above the ground.
If your mass is 65 kg, how much work does the elevator do to
get you to your floor?
2. A wood pecker’s beak hits the bark of a tree with a force of
4.90N although the mass of its head is only 5g. What is the
acceleration from rest of each stroke?
3. Assuming the beak penetrates into the treebark 0.75 cm, how
much work does the woodpecker do with each stroke?
4. You have hitched your horse to an Amish buggy for a ride
with your new sweetheart. The horse trots at 12 km/hr for 45
minutes to get to the barn raising, applying a steady force of
1720 Newtons. How far away was the barn raising?
5. How much work did the horse do in Joules?
6. If the motion of the buggy is opposed by a frictional force of
43 Newtons, what is the net work the horse did in Joules?
7. You drive your Dad’s new Prius home over the same route.
It gets there in 5 minutes. What was its acceleration?
8. The Prius weighs 2420 kg. What is the the force it exerts to
cover the distance in 5 minutes?
9. The Prius is heavier than the buggy, so its frictional force is
72 Newtons. What is the net work done by the Prius?
10.
How many Kilowatt-hours will you have to pay for to
recharge it so that your Dad won’t be angry about the battery
getting run down?