5 Written questions
5 Matching questions
- An example of an inclined plane.
- ---> ----> Doing work?
- what is mechanical efficiency?
- What is the formula to calculating work?
- if you are carrying a suitcase,are you doing work on the suitcase? why or why not?
- a 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.
- b Yes
- c 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.
- d pushing a piece of heavy furniture up a ramp requires less input force, from you, than just lifting it up.
- e W= F x D, the unit Joule
5 Multiple choice questions
- No, the same amount of work is done, whether you do it yourself, or use a machine.
- a double inclined plane that moves.
- a simple machine that has a fulcrum, or pivot point.
- Machines can change the size of the input force necessry. Also, they can change the direction of the force, which is especially helpfulo when we are trying to life somthing.
5 True/False questions
^ ^ Doing work? → Yes
What is the formula for power? → P=W / T, the unit Watts
^ <--- Doing work? → No
Whats a wheel and axle? → turn a door knob (the wheel) the axle moves, to unfasten the door.
What are compound machines? → a machine made of two or more simple machines. example: scissors, can openers