# Science-Energy Unit Flashcards

1
Q

A high energy electromagnetic wave has what wavelength

A

Short

2
Q

A high energy electromagnetic wave has what frequency

A

High

3
Q

Math related

How much work must be done to lift a heavy object from a height where it has 1200 J of GPE to a height where it has 3300 J of GPE?

A

+2100 J

Subtract 3300 and 1200

4
Q

Math related

A 15 kg box has 800 J of GPE. How high up is it?

A

5.44

Divide 800 by 15 then you get 53.3- and divide that by 9.8/gravity

Adding 15 and 9.8 then dividing that into 800 doesn’t work the same

5
Q

Math related

How much kinetic energy does a 0.4 kg ball have if it is moving at a speed of 40 m/s?

Equation for KE: ke=1/2mv^2

A

320 J

Square 40 then multiply it by 0.4 and 0.5.

6
Q

Math related

How much energy does a 7 kg monkey have if it is swinging at a speed of 6 m/s and at a height of 10 m?

I need help on this cuh

A

812 J

7
Q

A skateboarder is stationary on top of a hill. At this point the skateboarder has 3,000 J of potential energy. The skateboarder rides down the hill, and as they do so friction does -500 J of work on them.
At the bottom of the hill, how much kinetic energy does the skateboarder have?

A

2,500 J

I just subtracted 500 from 3000

8
Q

Air hits a windmill with 300,000J of kinetic energy, turning the windmill. This causes the windmill to produce 45,000 J of electrical energy and 25,000 J of heat. How much kinetic energy does the air have left after going through the windmill?

A

230,000 J

Add 45,000 and 25,000 and subtract that from 300,000

9
Q

How much energy does a car gain if it is pushed with 1,000 N of force over a distance of 50m?

A

50,000 J

Multiply 1,000 and 50,000

10
Q

If you were to go from Earth to the moon:

A

Your mass would be the same, but your weight would be less

11
Q

A battery converts energy from…to…

A

Chemical PE to Electrical energy

12
Q

A fan is running in the room, imparting kinetic energy on the air. After the fan has been turned off, and the air stills, what type of energy has the air’s kinetic energy transformed into?

A

Thermal Energy

I think it’s cuhz it’s cold air now

13
Q

Making bonds is

A

Endothermic

It absorbs energy making bonds

14
Q

Breaking bonds is

A

Exothermic

It releases energy breaking bonds

15
Q

When you hold an ice cube, your hand feels cold. Explain why this is?

A

Thermal energy flows from your hand to the ice cube

16
Q

When metallic sodium is placed into water, the reaction causes the water’s temperature to rise. Which conclusion can you reach?

A

Chemical potential energy was released as thermal energy because the reaction was exothermic

17
Q

Evaporation is endo or exo

A

Exothermic

18
Q