AQA AS Physics

Topic Questions

4.1 Scalars & Vectors

1a3 marks

Figure 1 shows a uniform beam supported by two light cables, AB and AC, which are attached to a single steel cable from a crane. The beam is stationary and in equilibrium. 

Figure 1

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The tension in cable AB is equal to T1 and the tension in cable AC is equal to T2. The weight of the beam is 9.5 kN. 

Draw a vector diagram to show the arrangement of the forces, including the angles.

1b2 marks

Write two equations to show the vertical and horizontal components of the forces in part (a).

1c2 marks

Calculate the tension T1 in cable AB.

1d2 marks

Calculate the tension T2 in cable AC. 

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2a2 marks

The helicopter shown in Figure 1 is moving horizontally through still air. The lift force from the helicopter’s blades is labelled A. 

Figure 1

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The lift force, A, is 12.0 kN and acts at an angle of θ to the horizontal. At any point, the lift force is always four times larger than the drag force. 

Draw a vector diagram to show the arrangement of the forces.

2b3 marks

Show the angle θ is about equal to 76˚.

2c3 marks

Calculate the weight of the helicopter. Give your answer to an appropriate number of significant figures.

2d3 marks

The helicopter begins to descend at a constant speed at an angle of 15° to the horizontal. 

Draw a vector triangle to represent the new forces acting on the helicopter.

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3a1 mark

Figure 1 shows two of the forces acting on a uniform ladder resting against a vertical wall. 

Figure 1

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Explain how Figure 1 shows that the friction between the ladder and the wall is negligible.

3b2 marks

The forces acting on the ladder are in equilibrium. 

Draw an arrow on Figure 1 to show the direction of the resultant force from the ground acting on the ladder. Label your arrow G.

3c2 marks

The reaction at the ground acts at an angle of 60o to the horizontal. The ladder weighs 140 N. 

Calculate the magnitude of the resultant force G from the ground acting on the ladder.

3d3 marks

If the wall was removed, only the weight W and reaction at the ground G would act, and the ladder would begin to topple. 

State the direction of the resultant force R and calculate its magnitude.

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4a1 mark

Figure 1 shows a uniform steel girder being held horizontally by a crane.

Two cables are attached to the ends of the girder and the tension in each of these cables is T.

Figure 1

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On Figure 1 draw an arrow to show the line of action of the weight of the girder.

4b2 marks

The tension, T, in each cable is 650 N. 

Calculate the horizontal component of the tension in each cable.

4c2 marks

Calculate the vertical component of the tension in each cable.

4d2 marks

Calculate the weight of the girder.

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5a3 marks

Figure 1 shows a 500 kg iron ball being used on a demolition site. 

Figure 1

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The ball is suspended from a cable which makes an angle θ with the vertical, and is pulled into the position shown by a rope that is kept horizontal. The tension in the rope is 1600 N. 

Determine the magnitude of the vertical component of the tension in the cable and write an expression relating the angle θ with the vertical and T.

5b3 marks

Determine the magnitude of the horizontal component of the tension in the cable and write an expression relating the angle θ with the vertical and T.

5c3 marks

Determine the angle θ the cable makes with the vertical.

5d2 marks

Determine the magnitude of the tension in the cable.

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