(A) the Load Is Moved Away from the Pivot, to the Right

1. The diagram shows a crane lifting a load. The counterweight and the load are balanced.

(a) The load is moved away from the pivot, to the right.

(i) What happens to the turning moment produced by the load?

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1 mark

(ii) What should happen to the counterweight to keep the arm balanced?

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1 mark

(b) A load of 5000 N is placed 8 m from the pivot.

(i) What is the turning moment of the load? Give the unit.

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2 marks

(ii) How far from the pivot must the 10000 N counter weight be placed in order to balance the load?

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1 mark

(iii) The counterweight is placed 3 m from the pivot.
What load could now be balanced 8 m from the pivot?

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1 mark

Maximum 6 marks

2. The diagram shows a simple tool for punching holes in a leather belt.

not to scale

When the handle is pressed down, the steel peg presses down on the piece
of leather. If the force is large enough, the peg punches through the leather,
making a hole.

The diagram below shows the force applied to the handle.

not to scale

(a) Calculate the moment (turning effect) of the 50 N force applied to the
handle. Give the units.

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2 marks

(b) This moment makes the steel peg press down on the leather. Calculate the force with which the steel peg presses down on the leather.

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1 mark

(i) The area of the end of the steel peg is 0.1 cm2.
What is the pressure of the steel peg on the leather?
Give the units.

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2 marks

(ii) The pressure is too small, and the punch does not go through the
leather. How could you change the design of the punch to make it
work using the same force on the handle?

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1 mark

Maximum 6 marks

3. The diagram shows a lever. A weight is near the end of the lever. A force, F, pushes up on the pad and balances the lever.

(a) The 50 N weight is pulling the lever anticlockwise around the pivot.
Calculate the moment (turning effect) of the 50 N weight about the pivot.
Give the units.

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2 marks

(b) The force F is just big enough to keep the lever balanced.

(i) What is the moment of force F about the pivot?

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1 mark

(ii) What is the size of force F?

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1 mark

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1 mark

(ii) The size of force F on the pad is 100 N. The area of the pad is 2 cm2.
Calculate the pressure of this force on the pad. Give the units.

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2 marks

Maximum 7 marks

A bell in a church tower is attached to a wheel of radius 0.8 m. The bell is balanced upside down. The bell-ringer pulls the rope with a force of 50 N.

(a) Calculate the moment (turning effect) on the wheel. Give the unit.

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2 marks

(b) The bell turns. When the rope is travelling at its highest speed, it moves 0.5 m in 0.04 s.
What speed is this? Give the unit.

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2 marks

-(c) The bell rings twice but the second ring is quieter than the first. Both rings have the same pitch.

Complete the sentences below to compare the two rings.

The amplitude of the second ring was ………………………… the amplitude of the first ring.

The frequency of the second ring was ……………………..….. frequency of the first ring.

2 marks

(d) The sound of a bell is within the audible range of most people.

Which is most likely to be the frequency of the sound made by a bell?
Tick the correct box.

1 mark

(e) The energy given out when the bell rings was originally stored in the bell-ringer.

Describe the main sequence of useful energy transfers which take place when a bell-ringer rings a church bell.

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3 marks

Maximum 10 marks

5. Gareth is trying to release a nut with a spanner. The diagram shows the size of the force he is exerting and where this force acts on the handle.

(a) The spanner applies a moment, or turning effect, to the nut. Calculate the size of this moment or turning effect. Give the units.

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2 marks

(b) Give two ways in which Gareth could increase the moment he applies using this spanner.

1 ..................................................................................................................................

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2 ..................................................................................................................................

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2 marks

Maximum 4 marks

6. A ladder is hung on one hook so that it balances horizontally.

Draw an arrow on the diagram below to show the position of the hook.

1 mark

(b) A window cleaner puts the ladder on his shoulder in the position shown.

(i) The weight of the ladder acts at its centre, as shown. Calculate the turning effect, or moment, about his shoulder due to the weight of the ladder. Give the unit.

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2 marks

The window cleaner hooks his bucket onto the ladder as shown in the diagram.
The bucket weighs 15 N and is 0.8 m from his shoulder.

(ii) Calculate the turning effect, or moment, about his shoulder due to the weight of the bucket only.

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1 mark

(iii) Calculate the size and direction (clockwise or anticlockwise) of the total turning effect, or moment, about his shoulder due to the weight of the ladder and the weight of the bucket.

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1 mark

(i) How can he move the ladder on his shoulder to reduce the force his hand has to balance?

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1 mark

(ii) How could he change the position of the bucket to reduce the force his hand has to balance?

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1 mark

Maximum 7 marks