IPC- Chapter 14

Chapter 14 into to physics and chemistry.

what is work?

using a force to move an object a distance (when both the force and the motion of the object are in the same direction)

what is the formula for work?

work = force x distance

what is the unit for work?

joules (J)

what is one joule equal to?

one newton meter

what is power?

the rate at which work is done

what is the formula for power?

power = work/time

what are the units for power?

watts (W) and horsepower (hp)

power and time are _______ _______

inversely proportional (more power means less time

what are six simple machines?

1. lever

2. wheel and axel

3. pulley

4. inclined plane

5. wedge

6. screw

what is a machine?

a device that changes a force

how do machines help you do work?

by redistributing the work that we put into them

machines make work ______ to do

easier

what is one horsepower equal to?

about 746 watts

the force exerted on a machine is the ______ _____.

input force

the distance the input force acts through is the _____ ________.

input distance

the force exerted by a machine is called the _______ _____.

output force

the distance the output force is exerted through is the ______ ________.

output distance

what is the only way to increase the work output of a machine?

increase the amount of work you put in the machine

true or false: you cannot get more work out of a machine than you put into it.

true

what is the mechanical advantage of a machine?

the number of times that the machine increases an input force

why is the actual mechanical advantage of a machine always less than the ideal mechanical advantage?

because friction is always present

what is the formula for mechanical advantage?

output force (N)/input force (N)

what is the ideal mechanical advantage (IMA) of a machine?

the mechanical advantage in the absence of friction

what is the formula for ideal mechanical advantage?

input distance/output distance

true or false: because friction reduces mechanical advantage

engineers often design machines that use low-friction materials and lubricants.

what is the efficiency of a machine?

the percentage of the work input that becomes work output

why is the efficiency of any machine always less than 100 percent?

because there is always some friction

the work ______ is always more than the work ______.

input

reducing ______ increases the efficiency of a machine.

friction

efficiency is usually expressed as a _________.

percentage

what is the formula for efficiency?

efficiency = work output/work input (expressed as a percentage)

how many types of levers are there?

3 types