Posted by Emily on Wednesday, December 9, 2009 at 10:44pm.
1A car is lifted a certain distance in a service station and therefore has potential energy with respect to the floor. If it were lifted twice as high, how much potential energy would it have?
Answer: twice as much
2Two cars, one twice as heavy as the other, are lifted to the same elevation in a service station. How do there potential energies compare?
Answer: The heavy object has more potential energy?
3if a car travels at 50 km/h, it has kinetic energy. How much more kinetic energy does it have at 100 km/h?
Answer=100 squared as much (10000)
4a force of 50N applied to the end of a lever moves that end a certain distance. If the other end of the lever is moved half as far, how much force does it half.
Answer=twice as much because a small input force produces a large output force?? Or does that only apply to levers when the fulcrum of the relatively close to a load.
5is it possible to design a machine that has an efficiency that is greater than 100%? Discuss.
Answer: no because the machine converts a small fraction of input energy into heat.

Physics  sarah, Wednesday, December 9, 2009 at 10:55pm
a car is traveling at 31.6mi/h on a horizontal highway. the acceleration of the earth is 9.8. if the coefficient of friction is .13, what is the minimum distance in which the car will stop?