5 Written questions
5 Matching questions
- if you are carrying a suitcase,are you doing work on the suitcase? why or why not?
- What is the formula to calculating work?
- what is a screw?
- does a machine reduce the amount of work that is being done? Explain.
- What is a pulley?
- a No, the same amount of work is done, whether you do it yourself, or use a machine.
- b W= F x D, the unit Joule
- c a inclined plane that is wrapped in a spiral, usually on a rod, but not always.
- d simple machine that is made of a wheel with a groove in it and a rope. it is usually used to life heavy objects.
- e No. you are doing work on it when you pick it up, b/c when you pick it up, the direction of the movement of the object is the same as the direction of the force you are putting on it.
5 Multiple choice questions
- it means that the machine multiplies the force you put into it twenty times. so, if the machine multiplies the force by 20, you would only have to put in a small amount of force to do a large amount of work.
- you are only doing work on the ball as long as you are directly putting a force on it, in other words, when you are touching it.
- is a measure of how much of a machines energy is wasted, overcoming friction. No machine is 100% efficient, becuase there are always surfaces rubbing together.
- P=W / T, the unit Watts
- the rate at which work is done.
5 True/False questions
if you are pushing against a wall, are you doing work? explain. → No. work is only done when the object moves. if the object doesnt move, no matter how much force you put on it, it isnt work.
Whats a wheel and axle? → a simple machine that is made of a circular object connected to a rod.
What is a lever? list two other examples of a lever. → a simple machine that has a fulcrum, or pivot point.
What are compound machines? → a device that helps make work easier by changing the size or direction of a force.
^ ^ Doing work? → Yes