{{asɛmtiNe Ɔkyerɛwfo}} | Nhomakorabea | Nneɛma a ɛma wotumi yɛ ade

Do Now

1

After being stretched, springs return to their original shape because they are…

1

Which law states that the extension of a spring is proportional to the force applied to it?

1

State the pH of an alkali

1

Which technique could be used to separate the different coloured chemicals in a sample of ink?

1

1.Put the following numbers in order from smallest to largest: (1)
5, 6, 2, -2, -5

1

Challenge: If something is falling at a constant speed, what does that tell us about the forces acting on it?

Mulitple choice quiz

1

Friction is a…

Contact force

Non-contact force

1.Heated force

1

Friction always acts in the…

Same direction to an object’s movement

Opposite direction to an object’s surface

Opposite direction to an object’s movement

1

Lubricants are used to…

Reduce friction

Increase friction

Keep friction the same

1

Lubricants work by…

acting as a layer between the smooth surfaces which makes it easier for the surfaces to move over each other.

acting as a layer between the rough surfaces which makes it easier for the surfaces to move over each other.

acting as a layer between the rough surfaces which makes it harder for the surfaces to move over each other.

Key Knowledge

1

What type of force is friction?

1

What type of force is friction?

1

Where does friction act?

1

Where does friction act?

1

In what direction does friction act?

1

In what direction does friction act?

1

How can we reduce friction?

1

How can we reduce friction?

1

Which has more friction a rough surface of a smooth surface?

1

Which has more friction a rough surface of a smooth surface?

I DO/ We Do/ You Do

1

Is the person in each picture trying to increase or decrease the amount of friction acting on them?

1

Is the person in each picture trying to increase or decrease the amount of friction acting on them?

1

Is the person in each picture trying to increase or decrease the amount of friction acting on them?

1

Challenge
A ball is dropped inside a vacuum (there are no air particles). Explain the effect this will have on the motion of the ball.

1

Explain how friction can be useful and unhelpful

Exam style question practice

1

A railway engine is being used to try to pull a wagon along a level track. The wagon’s brakes are on, and the wagon does not move.
(i) Draw one arrow on the diagram to show the direction of the force which prevents the wagon from moving.
1 mark
(ii) Is the force which prevents the wagon from moving greater than, equal to or less than the pull of the engine?
.............................................................................................................
1 mark

1

b) (i) When the wagon’s brakes are off, the engine pulls the wagon forwards. A frictional force also acts on the wagon. In what direction does the frictional force act?
1 mark

1

(ii) The pull of the engine is 5000 N. When the wagon’s speed is increasing, how large is the frictional force?

Zero

between 0 and 5000 N

5000 N

more than 5000 N

1

After a while, the wagon travels at a steady speed. The engine is still pulling with a force of 5000 N.
How large is the frictional force now?

Zero

between 0 and 5000 N

5000 N

more than 5000 N

Friction (KBl) OALH

Friction (KBl) OALH

After being stretched, springs return to their original shape because they are…

Which law states that the extension of a spring is proportional to the force applied to it?

State the pH of an alkali

Which technique could be used to separate the different coloured chemicals in a sample of ink?

1.Put the following numbers in order from smallest to largest: (1)5, 6, 2, -2, -5

Challenge: If something is falling at a constant speed, what does that tell us about the forces acting on it?

Friction is a…

Friction always acts in the…

Lubricants are used to…

Lubricants work by…

What type of force is friction?

What type of force is friction?

Where does friction act?

Where does friction act?

In what direction does friction act?

In what direction does friction act?

How can we reduce friction?

How can we reduce friction?

Which has more friction a rough surface of a smooth surface?

Which has more friction a rough surface of a smooth surface?

Is the person in each picture trying to increase or decrease the amount of friction acting on them?

Is the person in each picture trying to increase or decrease the amount of friction acting on them?

Is the person in each picture trying to increase or decrease the amount of friction acting on them?

ChallengeA ball is dropped inside a vacuum (there are no air particles). Explain the effect this will have on the motion of the ball.

Explain how friction can be useful and unhelpful

b) (i) When the wagon’s brakes are off, the engine pulls the wagon forwards. A frictional force also acts on the wagon. In what direction does the frictional force act?1 mark

(ii) The pull of the engine is 5000 N. When the wagon’s speed is increasing, how large is the frictional force?

After a while, the wagon travels at a steady speed. The engine is still pulling with a force of 5000 N.How large is the frictional force now?

After being stretched, springs return to their original shape because they are…

Which law states that the extension of a spring is proportional to the force applied to it?

State the pH of an alkali

Which technique could be used to separate the different coloured chemicals in a sample of ink?

1.Put the following numbers in order from smallest to largest: (1)5, 6, 2, -2, -5

Challenge: If something is falling at a constant speed, what does that tell us about the forces acting on it?

Friction is a…

Friction always acts in the…

Lubricants are used to…

Lubricants work by…

What type of force is friction?

What type of force is friction?

Where does friction act?

Where does friction act?

In what direction does friction act?

In what direction does friction act?

How can we reduce friction?

How can we reduce friction?

Which has more friction a rough surface of a smooth surface?

Which has more friction a rough surface of a smooth surface?

Is the person in each picture trying to increase or decrease the amount of friction acting on them?

Is the person in each picture trying to increase or decrease the amount of friction acting on them?

Is the person in each picture trying to increase or decrease the amount of friction acting on them?

ChallengeA ball is dropped inside a vacuum (there are no air particles). Explain the effect this will have on the motion of the ball.

Explain how friction can be useful and unhelpful

b) (i) When the wagon’s brakes are off, the engine pulls the wagon forwards. A frictional force also acts on the wagon. In what direction does the frictional force act?1 mark

(ii) The pull of the engine is 5000 N. When the wagon’s speed is increasing, how large is the frictional force?

After a while, the wagon travels at a steady speed. The engine is still pulling with a force of 5000 N.How large is the frictional force now?

1.Put the following numbers in order from smallest to largest: (1)
5, 6, 2, -2, -5

Challenge
A ball is dropped inside a vacuum (there are no air particles). Explain the effect this will have on the motion of the ball.

b) (i) When the wagon’s brakes are off, the engine pulls the wagon forwards. A frictional force also acts on the wagon. In what direction does the frictional force act?
1 mark

After a while, the wagon travels at a steady speed. The engine is still pulling with a force of 5000 N.
How large is the frictional force now?

1.Put the following numbers in order from smallest to largest: (1)
5, 6, 2, -2, -5

Challenge
A ball is dropped inside a vacuum (there are no air particles). Explain the effect this will have on the motion of the ball.

b) (i) When the wagon’s brakes are off, the engine pulls the wagon forwards. A frictional force also acts on the wagon. In what direction does the frictional force act?
1 mark

After a while, the wagon travels at a steady speed. The engine is still pulling with a force of 5000 N.
How large is the frictional force now?