Work
Is pushing a wall doing work?
no
A machine can make work easier in three ways- list them
size distance direction
How would you find power if you only had values for seconds force and distance?
power equals (force x distance) / time
When a roller coaster is going down hill its _______ energy is changing to _____________ energy
Potential to Kinetic
A machine makes a task easier but does not do what?
Change the amount of work required
What is the scientific definition of doing work?
Using a force to move an object
Why can't the efficiency of a machine never reach 100%?
Friction
Name the 3 units used in the power equation
Joules, Watts, Seconds
this is where a roller coaster had the most potential energy
at the top of a hill
Efficiency is always expressed as a _____
%
What is equal to one newton-meter?
Joule
Joe does 300J of work pulling the rope on a pulley to lift a crate. The output work of the pulley is 230J. What is the efficiency?
77%
Karla does 25J of work in 5.0 second carrying her clean clothes upstairs. How much power did Karla use on the clothes?
5W
the place where a roller coaster has the most kinetic energy
at the bottom of a hill
What kind of energy do all moving objects have
kinectic
The teacher lifts 3 books 5 meters off the floor. She does 10 Joules of work. How much force did she apply?
2N
Mark applies a force of 6 N to a rake. The rake has an output force of 12 N. What is the mechanical advantage of the rake?
MA= 2
How much power is needed to do 1,000 joules of work on a box if it takes 50 seconds to lift it?
20W
Doing work on an object by moving it sideways transfers what type of energy to the object?
kinetic energy
A machines ______ is determined by comparing the input and output forces
MA
You use 200N of force to push a snow shovel 100m along the ground. How much work was done?
20,000J
If Jennie applies an input force of 100 N to a level that has a MA of 3, what is the output force by the lever?
300N
How much work is done if 500W of power is used over 2 minutes
60,000J
Caleb slid his book over the table. Which type of energy is transferred to the book?
Kinetic energy
How many centimeters are in a meter
100