Physics Test 3- Work & Energy

Question 1

What is the formula for Kinematic Energy?

Answer 1

KE = 1/2(m)(v^2)

Question 2

What is the formula for Spring Energy

Answer 2

EPE = 1/2(K)(X^2)
K is the spring constant.
X is distance.

Question 3

What is the formula for Potential Energy?

Answer 3

PE = mass times gravity times height

Question 4

Is Potential Energy Linear?

Answer 4

Yes

Question 5

What is a Joule?

Answer 5

The unit for Energy. 1 Joule = 1 Newton times 1 meter

Question 6

What is work?

Answer 6

Work is the product of a force and displacement that are in the same direction (parallel).
W = F(d)
Work is a squalor quantity

Question 7

What is Power?

Answer 7

Power = work / time. Measured in Watts.

Question 8

What are the 3 conditions for work to be done?

Answer 8

You need a force
You need a displacement
They need to be parallel

Question 9

A vector times a squalor equals what?

Answer 9

A vector

Question 10

A vector times a vector equals what?

Answer 10

A squalor

Question 11

What are some examples of instances which energy could be lost?

Answer 11

Heat, friction, maintaining body temperature, replacing skin

Question 12

Why is the human body less than 5% efficient?

Answer 12

Because keeping the body alive takes energy

Question 13

What is Hooke’s Law?

Answer 13

Force = K(X)

Question 14

What’s the definition of elastic?

Answer 14

Anything that can be deformed but will return to its original position. It does this with stored energy called ‘Elastic Potential’. This means it conserves kinetic energy.

Question 15

What is the unit for a spring constant (K)?

Answer 15

Newton per meter

Question 16

What is the proof for EPE = 1/2(K)(x^2)

Answer 16

Area of triangle = 1/2(b)(h) = 1/2 (x)(F) = 1/2(x)(kx) = 1/2(k)(x^2)

Question 17

What are the stages of a vertical spring?

Answer 17

1. Spring is compressed. All EPE
2. Sprint begins to launch. No EPE. All PE and KE
3. Spring is fully launched. All PE. Height and velocity are max

Question 18

What are the stages of a horizontal spring?

Answer 18

1. Spring is compressed. All EPE. Velocity = 0
2. Spring is beginning to launch. All KE. Max velocity
3. Spring is fully launched. All EPE. Velocity = 0

Question 19

What are four spring examples?

Answer 19

1. Bow and Arrow
2. Pogo stick
3. Slingshot example
4. Small vertical spring and tennis ball.

Question 20

What is a vector?

Answer 20

Any quantity in Physics with a size and a direction.

Question 21

What are some other units for watts?

Answer 21

-Joules per second
-Newton times meter per second
-(Kilogram meter per second squared times meter)(second)
-Kilogram times a meter squared per second cubed

Question 22

Who was James Watt?

Answer 22

A Scottish Engineer who made improvements to the steam engine. Tested Dray horses to discover horse power.

Question 23

What is the formula for efficiency?

Answer 23

(Output/input)(100)

Question 24

What is the Law of Conservation of Mechanical Energy?

Answer 24

ME = ME Prime

Question 25

What is Mechanical Energy?

Answer 25

Energy with no friction or heat loss. Total energy is conserved

Question 26

What is a conservative force?

Answer 26

Work is done on an independent path. No friction or heat loss.

Question 27

What is a non conservative force?

Answer 27

Work depends on the path

Question 28

What are examples of conservative forces?

Answer 28

Electric, gravitational, elastic

Question 29

What are examples of non conservative forces?

Answer 29

Friction, applied, push-pull, tension