Energy

Question 1

What is the potential energy of a ball in the air when the mass is 4.8kg and the height it’s at is 18metres?

Answer 1

Ep=mgh

Ep=4.8x9.8x18

Ep=846.72J

Question 2

What type of energy is the easiest to transport when using cables?

Answer 2

Electrical Energy

Question 3

What is the kinetic energy of a car when the mass is 80kg and the speed its traveling at is 40m/s?

Answer 3

Ek=1/2 mv²

Ek=40x1600

Ek=64,000J

Question 4

Which energy is the energy of movement?

Answer 4

Kinetic Energy

Question 5

What is the formula for Electrical energy?

Answer 5

Ee=ItV

Question 6

What type of energy is transferred to a body that results in a change in the body’s temperature?

Answer 6

Heat Energy

Question 7

What does Ek stand for?

Answer 7

Kinetic Energy

Question 8

What is the number we use to represent gravity in the Potential Energy calculation?

Answer 8

9.8

Question 9

What does Ep stand for?

Answer 9

Potential Energy

Question 10

What type of energy can be best described as stored in a static object?

Answer 10

Potential Energy

Question 11

What does Eh stand for?

Answer 11

Heat energy

Question 12

What does Ee stand for?

Answer 12

Electrical Energy

Question 13

What is the electrical energy in a lamp if the current is 5A, the voltage is 230V and the time it has been switched on has been 3 minutes?

Answer 13

Ee=ItV

Ee=5x230x180

Ee=207,000J

Question 14

A kettle contains 0.5litres of water at 3 degrees. How much heat energy is needed to raise the temperature to 100 degrees? (The specific heat capacity of water is 4,200kJ/kgk)

Answer 14

Eh=mcΔT

Eh=0.5x4200x97

Eh=203,700J

Question 15

Find the mass of a car when its Kinetic Energy is 300J and the velocity is 50ms^-1.

Answer 15

Ek=1/2mv²

1/2m=Ek/v²

1/2m=300/50²

m=0.12x2

m=0.24kg

Question 16

Calculate the difference in temperature when the specific heat capacity of water is 4200kJ/kgk, the heat energy is 102,000J and the mass 0.75kg.

Answer 16

Eh=mcΔT

ΔT=Eh/(mxc)

ΔT=102,000/(0.75x4,200)

ΔT=32.38°

Question 17

What is the height of the ball if it’s Potential Energy is 1230J and the mass is 0.6kg?

Answer 17

Ep=mgh

h=Ep/mg

h=1230/(0.6x9.8)

h=209.18m

Question 18

What is the current in the circuit if the voltage is 6v, the time is 6.5 minutes and the Energy in the circuit is 1165J?

Answer 18

Ee=ItV

I=Ee/tV

I=1165/(390x6)

I=0.5A