Forces and Energy

Question 1

Complete the sentence: When a system changes, energy is………

Answer 1

transferred

Question 2

Name 3 ways energy can be transferred.

Answer 2

By Heating, by forces doing work or by electrical equipment.

Question 3

What is a closed system?

Answer 3

A closed system is one that’s defined so that the net change in energy is 0.

Question 4

What is work done?

Answer 4

A force moving on an object.

Question 5

What is the equation for work done?

Answer 5

E=Fd

Question 6

Calculate the distance travelled in km if a 5kN force acts on an object with a work done of 15kJ

Answer 6

3km

Question 7

What is power?

Answer 7

How much work is done per second

Question 8

What is power measured in?

Answer 8

Watts (W)

Question 9

What is the formula for Power?

Answer 9

P=E/t

Question 10

Calculate the work done in mJ if a 650W microwave runs for 1.24hours.

Answer 10

2.9016mJ

Question 11

What causes forces?

Answer 11

Interactions between objects.

Question 12

Give an example of a non-contact force.

Answer 12

gravity

Question 13

Give an example of a contact force.

Answer 13

Friction

Question 14

What do free-body force diagrams show?

Answer 14

All the forces acting on an object

Question 15

What is a resultant force?

Answer 15

The overall force on a point or object.

Question 16

What is the resultant force of an object in equilibrium?

Answer 16

0

Question 17

What is the resultant force of a car if the forward force is 5kN and the frictional forces are equal to 1400N?

Answer 17

3600N or 3.6kN

Question 18

What 2 components can a force be split into?

Answer 18

horizontal and vertical

Question 19

What is a moment?

Answer 19

The Turning effect of a force

Question 20

What is the formula for moment

Answer 20

Moment=Force x distance normal to the direction of the force.

Question 21

Calculate the moment if a 50cm long spanner is turned with a force of 6.5N.

Answer 21

3.25Nm

Question 22

What do gears transmit?

Answer 22

Turning forces.

Question 23

The larger the gear, does the speed that it spins increase or decrease.

Answer 23

Increase.