⭐️Topic SP8/SP9-Forces Doing Work And Their Effects

Question 1

What is work done?

Answer 1

The energy transferred by a force

Question 2

How can you calculate work done?

Answer 2

Work done (J)= force (N) x distance moved in the direction if the force (m)

Question 3

Danny is moving a box weighing 300N. He pulls in 3m along a skipping ramp using a force of 200N. Calculate the work done Danny does.

Answer 3

E (work done) = F (force) x d (distance)
= 200N x 3m
= 600J

Question 4

What is power?

Answer 4

The rate at which energy is transferred

Question 5

Power is also the rate of doing work…

Answer 5

When energy is being transferred by forces

Question 6

What is power’s unit? What does this mean?

Answer 6

Watt (W) and 1 watt means 1 joule if work done per second

Question 7

How can you calculate power?

Answer 7

Power (W) = work done (J) / time taken (s)

Question 8

What is the force between two objects that are touching called?

Answer 8

Contact force

Question 9

Name a pair of contact forces on a boat

Answer 9

The force from the engine and water resistance as the engine keeps the boat moving as water resistance slows it down

Question 10

What kind of force is gravity?

Answer 10

A non-contact force

Question 11

What are action reaction forces?

Answer 11

Pairs of forces acting on different objects in opposite directions

Question 12

How does gravity work on the moon in respect to the earth?

Answer 12

It causes the two bodies to attract each other

Question 13

What kind of force is the gravity that that hold the moon and the earth and acts in an opposite direction?

Answer 13

Action reaction force

Question 14

What’s a force field?

Answer 14

The space around an object where it can affect others

Question 15

Why do the moon and earth effect each other?

Answer 15

As the moon is within the earth’s gravitational field

Question 16

Give examples of a force field?

Answer 16

• gravitational field
• magnetic field
• electrostatic field

Question 17

What metals can a magnet attract?

Answer 17

Iron, nickel, colbat,

Question 18

How does an electric field effect two objects within it that have the same charge and are close together

Answer 18

They produce a pair of forces in equal size and acting in opposite direction

Question 19

What does it mean if a plane is flying at a constant velocity?

Answer 19

The horizontal and vertical forces on the plane are balanced

Question 20

What can a scale diagram be used to find?

Answer 20

The resultant force

Question 21

Give the steps to drawing a scale diagram in order to find the resultant force

Answer 21

• draw arrows at the correct angles to represent forces, length represents the size so you need a scale diagram
• draw lines to make a parallelogram
• the diagonal of the parallelogram is the resultant force and measure this to find the force

Question 22

How can you use scale diagrams to resolve the forces?

Answer 22

• draw a force arrow to scale at the correct angle
• draw a rectangle with sides in directions you’re interested in
• measure the sides of the rectangle for the resolved forces

Question 23

What is a moment?

Answer 23

A turning force

Question 24

How can you find moment of a force?

Answer 24

Moment ( N m) = force x distance perpendicular to direction of the force

Question 25

What’s the rule for when a system involving rotational forces is in equilibrium?

Answer 25

The sum of clockwise moments = sum of anti clockwise moments

Question 26

What’s a lever?

Answer 26

A bar that pivots about a point and is used to transfer a force

Question 27

What can gears do?

Answer 27

Transmit the rotational effect of a force

Question 28

Gear X has 10 teeth and is connected to gear Y which has 40. How many times will gear X turn for Y?

Answer 28

4 times

Question 29

Explain how the work is done when a ball is dropped and falls onto sand [2]

Answer 29

Work done displaces the sand [1] as kinetic energy from the ball has been transferred [1]