Force and Work
1. Define energy.
2. Define work.
3. Define force.
4. A force applied to an object tries to do what to it?
5. What conditions must be met for work to be done on an object.
6. If the force applied to an object is not enough to move it, has there been an energy transfer?
7. Assume that you are applying a constant force to an object. Explain how its mass affects its acceleration.
8. Define inertia.
9. How does inertia affect the amount of force required to move objects?
10. Which has more inertia, a 2000 kg rhinoceros moving at 5 m/s or a 2000 kg car travelling at 5 m/s? Explain.
11. Mitch smacks Jason, causing him to accelerate at 2 m/s2. Later, he hits Jason again but with a force that is three times the original force. What is the new acceleration?
12. What is the equation that relates an applied force attempting to move an object, the object's mass and the rate of acceleration at which the object travels? Identify the units for each variable in the equation.
13. An elephant pushing with a 3 000 N force against a 2 800 kg tree will cause it to accelerate at what rate?
14. a) As it turns out, Kristy is a terrible driver and puts her family car in the ditch. A tow truck pulling against the 700 kg car with a force of 800 N will cause it to accelerate at what rate?
b) Knowing the acceleration, at what velocity would the towed car be moving after 10 s if it started from rest?
15. a) Wanting to impress the ladies (and Mr. D), Wilkins bench presses 180 kg with a force of 170 N. What acceleration will the weights experience?
16. What force would be applied to a 50 kg box to cause it to accelerate at 0.7 m/s2?
17. A 340 kg rock could be accelerated at 1.4 m/s2 by a horse and chain applying what force?
18. A puck sits on a frictionless surface when Bruce makes a slapshot with a force of 16 N. If its mass is 0.25 kg, find its acceleration.
19. A 1 000 kg satellite would be accelerated at 3.7 m/s2 by a small manoeuvring rocket applying what force?
20. Suzanne is frustrated and tired of doing science stuff from the internet. To vent her feelings, she throws her 0.6 kg textbook, accelerating it at 4.7 m/s2. What force did she apply?
21. A 500 N applied force could cause a packing crate of what mass to accelerate at 0.6 m/s2?
22. Hess figures he could easily take out Swetnam with a rock to the temple. If Hess can apply a force of 20 N, a rock of what mass could be accelerated at 3.8 m/s2?
23. In a new cheerleading stunt, Meghan has to apply a force of 48 N to one of the other girls. What is the maximum mass she could accelerate at 7.3 m/s2?
24. Calculate the work done by the wind in moving a sailboat 400 m with a force of 500 N.
25. Jackie wants to be a good little student, so she helps her science teacher carry some text books upstairs. She exerts a force of 20 N to lift the books up one flight of stairs, a vertical distance of 4.6 m. Calculate the work done.
26. Dave (who isn't dead after all) steals a truck to go cruising around the bowling alley. He is travelling down the Marr Road at 28 m/s and the truck has a mass of 12 500 kg. Suddenly, he spots a honey walking along the road and he slams on the brakes. The truck takes 4.00 s and 56 m to stop. Calculate the work done by the brakes. Is the girl impressed?