Work
Power
Simple Machines I
Simple Machines II
Misc.
100
What is work?
Work is when you apply a force to an object and move it a distance
100
What is power?
How quickly work is done
100
What is a machine?
Machine is a device that makes work easier
100
List all 6 simple machines
Inclined Plane Screw Wedge Lever Wheel and Axle Pulley
100
Draw a diagram of a class 3 lever
F---IF ------------OF
200
What is the formula for work?
W= F x d
200
What is the formula for power?
P= W/t
200
What are 3 things a machine can do to make work easier?
Changes the force Changes the distance Changes the direction of the force
200
What is in the middle of a class 2 lever?
Load or output force
200
Give an example of a wheel and axle
Fan, doorknob, steering wheel, ferris wheel........
300
In what unit do we measure Work?
Joules
300
In which unit do we measure Power?
Watts
300
What do we call a machine that is made up of several simple machines?
Compound Machine
300
How does a screw make work easier?
Multiplies force
300
What are the three types of pulleys?
Fixed, Moveable, Block and Tackle
400
A boy climbs a ladder to the top of a building. He then uses an inclined plane to get to the top. Did the amount of work he did change?
No. The work stayed the same!
400
A girl carries a ball up a ramp for 15 s. She does 30 J of work. How much power did she exert?
P= W/t P= 30/15 P= 2 w The girl exerts 2 w of power.
400
How does an inclined plane make work easier?
Changes the distance and amount of force
400
What does it mean if we increase the mechanical advantage of a machine?
We made work easier.
400
Why are you doing no work when you carry your suitcase, and doing less work when you pull it on its wheels?
When you carry the suitcase the force and the motion are not in the same direction. When you pull a suitcase on its wheels then only part of the force is in the same direction as the motion.
500
A boy pushes a sled that weighs 10 N a distance of 5 m. How much work was done?
W= F d W= 10 x 5 W= 50 J The boy does 50 J of work.
500
A painter carries a 20 N bucket of paint up a staircase, doing 150 J of work. It takes 10 seconds to get up the ladder. How much power did he use while climbing the ladder?
P= W/t P= 150/ 10 P= 15 w The painter used 15 w of power.
500
How does a wedge make work easier?
multiplies force
500
What is the one thing a class 1 lever does to make work easier that a class 2 and class 3 lever does not.
Changes the direction of the force.
500
What effect does friction have on a machine's efficiency? How could you improve the efficiency of a machine?
Friction reduces efficiency. To improve efficiency change sliding or static friction to rolling or fluid friction.
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