Ch.14 Physics

Question 1

Is work done on an object that moves in the opposite direction of the force acting on it?

Answer 1

No

Question 2

What is the SI unit of work?

Answer 2

Joule

Question 3

What is power?

Answer 3

The rate of doing work

Question 4

How do you find power?

Answer 4

Dividing work over time

Question 5

What is the SI unit if power?

Answer 5

Watt

Question 6

How many joules of work is horsepower?

Answer 6

746J

Question 7

What does a machine do?

Answer 7

Changes the direction,size,and distance of force making work easier

Question 8

The work done by a machine is always less than the work done on a machine due to ________.

Answer 8

Friction

Question 9

How do you find work input?

Answer 9

Input force•input distance

Question 10

The number of times that a machine increases input force is the ________ ________.

Answer 10

Mechanical advantage

Question 11

Which has less friction a bumpy rough ramp or a smooth surfaced ramp? Which requires more force to get up?

Answer 11

Smooth surfaced ramp; bumpy rough ramp

Question 12

Does a rough loading ramp gave a greater MA than a smooth one?

Answer 12

No

Question 13

What is IMA?

Answer 13

MA in the absence of friction

Question 14

Is an inclined plane a machine?

Answer 14

Yes

Question 15

Why is efficiency always less than 100%?

Answer 15

Friction is always present

Question 16

Reducing friction ________ the efficiency of a machine.

Answer 16

Increases

Question 17

What are the six simple machines?

Answer 17

Lever,pulley,wedge,screw,wheel and axel, and inclined plane

Question 18

What is a screwdriver being used to open a paint can an example of?

Answer 18

Lever

Question 19

What is the fixed point that a lever rotates around?

Answer 19

Fulcrum

Question 20

What characteristics distinguish levers as first,second,or third class?

Answer 20

Fulcrum,input force,output force

Question 21

What is a slanted surface along which a force moves an object to different elevation?

Answer 21

Inclined plane

Question 22

Screws with threads closer together have a greater what?

Answer 22

IMA

Question 23

What is a simple machine consisting of rope fitted into a grooved wheel?

Answer 23

Pulley

Question 24

What is a compound machine?

Answer 24

A combination of two or more machines that operate together

Question 25

What three things are compound machines?

Answer 25

Watch,car,and washing machine

Question 26

What is work output over work input • 100?

Answer 26

Efficiency

Question 27

What does dividing output work by output force find?

Answer 27

Output distance

Question 28

What is the distance between the fulcrum and input force?

Answer 28

Input arm

Question 29

What is a machine has IMA that increases when it's thickness decreases relative to its length?

Answer 29

Wedge

Question 30

What is exerting in a jack handle to lift a car an example of?

Answer 30

Input force

Question 31

What is the distance between the output force and fulcrum?

Answer 31

Output arm

Question 32

What is the distance input force acts through?

Answer 32

Input distance

Question 33

In science, when work is done an ________ acts on an object in the direction the object moves.

Answer 33

Force