Simple Machines
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
卡片预览 (24 张)
True or false Applying a force always results in work being done
False, the object has to move
Define work
In science, work occurs when a force causes an object to move in the direction of that force
When do you know if work is being done
1) the object moves as a force is applied 2) the direction of the objects motion is the same as the direction of the force applied
Work formula & what is the unit for work
W=FxD Joules
Define power
The rate at which work is done.
Power formula & what is the unit for power
P=W divided by T Watt
How is powered increased
When work is done faster
Define machine
A device that helps make work easier by changing the size or direction or a force
Define input force
The work you do on the machine
Define output force
The work done by the machine
True or false Work output can never be greater than the work input
True
What is the force-distant trade off
When you increase force you decrease distance and when you increase distance you decrease force
Define mechanical advantage
Tells you how many times the machine multiplies force.
Equation for mechanical advantage
Output force divided by input force
Why can work output never be greater than work input.
Because some of the work is used to overcome friction, but no work is lost
Define mechanical efficiency
A comparison of a machines work output and work input
Equation for mechanical efficiency
Work output divided by work input. Then multiplied by 100
6 simple machines
Lever, inclined plane, wedge, screw, pulley, wheel & axle
Define lever
Simple machine consisting of a bar that pivots at a fixed point
Explain 1st class levers
The fulcrum is in the middle. Always changes the direction of the of the input force. Ex. Seesaw
Explain 2nd class levers
The load is in between the fulcrum and the input force. They allow you to apply less force than the force exerted by the load. Ex. wheelbarrow
Explain 3rd class levers
The input force is between the load and the fulcrum. The output force is less than the input force
Define inclined plane
Simple machine that is in a straight slanted surface
Equation for M.A for inclined plane.
Length divided by height