Forces

Question 1

What unit are forces meausred in?

Answer 1

Newtons

Question 2

What are forces?

Answer 2

Forces are pushes or pulls that make something start or stop moving

Question 3

State 7 different things that forces can do

Answer 3

Start something moving

Stop something moving

Twist things

Make things turn

Compress things

Stretch things

Balance each other out

Question 4

What do we call forces that have the same strength but point in opposite directions

Answer 4

Balanced forces

Question 5

What do we call two forces that act in different directions and have differnt sizes

Answer 5

Unbalanced

Question 6

In which direction does this ball speed up?

Explain why this happens

Answer 6

The ball will accelerate (speed up) to the right

This is because the forces are unbalanced. The ball moves to the right because the largest force is pointing to the right

Question 7

Explain why the Newton meter does not move in this picture

Answer 7

The newton meter does not move because the forces acting on it are balanced.

Question 8

Why does this bus (The Mystery Machine) move at a steady speed

Answer 8

The forces on The Mystery Machine are balanced. This means it does not speed up or slow down, so it must be moving at a constant speed.

Question 9

Which force slows things down when two surfaces rub together?

Answer 9

Friction

Question 10

Which force stops you from falling through the floor?

Answer 10

The normal reaction force

Question 11

Which force makes a boat float

Answer 11

Upthrust

Question 12

Which force pulls you towards the earth?

Answer 12

Weight

Question 13

Which force is caused by the pull of a stretched elastice band?

Answer 13

Tension

Question 14

Which force holds up a tower from the bottom?

Answer 14

Compression

Question 15

Which force acts on metals only and is caused by North and South poles

Answer 15

Magnetic force

Question 16

Which force slows down a falling skydiver

Answer 16

Air resistance (drag)

Question 17

What is the name of the force that speeds things up?

Answer 17

Thrust

Question 18

What causes the force of friction?

Answer 18

Friction is caused by rough surfaces rubbing against each other

The rougher the surfaces are, the larger the force of friction

Question 19

How can we reduce friction?

Answer 19

Lubricants, such as oil, reduce friction by filling in the gaps and stopping the rough surfaces from rubbing against each other.

Question 20

Explain what streamlining is

Answer 20

Stremlining is when the shape of an object helps to reduce air resistance, this is done by making the object longer or more pointy

Question 21

Explain when friction is useful or when friction is not useful

Answer 21

Friction is useful when we do not want things to slide, for example friction between your feet and the floor helps you to walk

Friction is not useful when you want to slide, for example friction between ice skates and the ice would slow you down so it is not helpful

Question 22

What is the difference between mass and weight?

Answer 22

Mass is the ammount of stuff there is

Weight is the force of gravity on an object

Question 23

Explain what this formula tells us

W = m x g

Answer 23

This force tells us that to find the force of weight we need to multiply together the mass of the object and the strength of gravity of that planet

W = Weight (N - Newtons)

m = mass (kg - kilograms)

g = strength of gravity (m/s² - meters per second squared)

Question 24

What is the relationship between the size of a planet and the strength of gravity?

How does this affect the weight?

Answer 24

The larger the planet the stronger the strength of gravity

If someone goes to another planet, their mass stays the same but the weight increases becuase the strength of gravity increases.

Question 25

What happens to the tension force of a spring when the string is stretched?

Answer 25

When the spring is stretched the force of tension increases.

Question 26

What is the resultant force in this picture.?

Explain how you work out a resultant force

Answer 26

The resultant force is 20N to the right.

You work out a resultant force by subtracting the smaller force from the bigger force. The direction is always the direction of the bigger force.