AQA AS Physics

Topic Questions

4.2 Moments

11 mark

What are the units of the moment of a force?

  • N m–1

  • N m

  • N s

  • N kg–1

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21 mark

Which of the statements about the required conditions for equilibrium is correct?

  1. The sum of the clockwise moments about a point equals the sum of the anticlockwise moments about the same point
  2. There is no resultant force
  • 1

  • 2

  • 1 & 2

  • neither

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31 mark

What is the centre of mass of an object?

  • the geometrical centre of the object

  • the point about which the total torque is zero

  • the point at which the weight of the object may be considered to act

  • the point through which gravity acts

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41 mark

The diagram below shows a beam in equilibrium.

q4_moments_aqa-as-physics-mcq

Which statement about the force at X is correct?

  • It is smaller than 100 N

  • It is also 100 N

  • It is larger than 100 N

  • Not enough information to know

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51 mark

The beam in the diagram below is in equilibrium by the three forces, X, 10.1 and 3.2 N.

q5_moments_aqa-as-physics-mcq

What is the value of the force X?

  • 2.9 N

  • 3.2 N

  • 6.8 N

  • 13.3 N

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61 mark

A pair of scissors requires 10 N of force on each handle in order to close the blades. 

q6_moments_aqa-as-physics-mcq

What force is applied by the scissor blades in the diagram below to cause the blades to come closer together?

  • 10 N

  • 20 N

  • 40 N

  • 100 N

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71 mark

Two co-planar forces act on the rim of a wheel. The forces are equal in magnitude.

Which arrangement of forces provides only a couple?

q7_moments_aqa-as-physics-mcq

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81 mark

Which of the following statements about the pair of forces on a couple is correct?

 

Magnitude

Direction

Parallel or Perpendicular

A

Equal in magnitude

Opposite in direction

Parallel to the distance between them

B

Equal in magnitude

Opposite in direction

Perpendicular to the distance between them

C

Opposite in magnitude

Equal in direction

Parallel to the distance between them

D

Equal in magnitude

Equal in direction

Perpendicular to the distance between them

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91 mark

A steering wheel of diameter 0.38 m is rotated to the left by two forces of 2 N, as show in the diagram.

q9_moments_aqa-as-physics-mcq

What is the moment of the couple produced by the rotation of the steering wheel?

  • 0.38 N

  • 0.50 N

  • 0.76 N

  • 1.0 N

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101 mark

A bird of mass 15 g sits on a uniform rod of mass 0.5 kg suspended from vertical wires with tension T1  and T2. T1 is 3 N and T2 is 2 N.

q10_moments_aqa-as-physics-mcq

What is the total clockwise moment about point P?

  • 0.053 N

  • 1.0 N

  • 1.2 N

  • 1.3 N

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11 mark

The diagram shows a uniform shelf along the axis XY with a mass 0.5 kg. A 3 kg load is placed at Y and a wire of tension T holds the shelf to the wall.

q21_moments_aqa-as-physics-mcq

What is the magnitude of the tension in the supporting wire?

  • 0.898 N

  • 10.4 N

  • 102 N

  • 280 N

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21 mark

The wedge shown in the diagram below is suspended in equilibrium by a cable at an angle of 120º to the longest part.

The wedge has a mass of 200 kg, with a centre of mass ¾ of the length of AB from the hinge at A. AB is 2 m long and BC is 1.2 m high.

q22_moments_aqa-as-physics-mcq

What is the tension on the cable?

  • 2900 N

  • 1700 N

  • 990 N

  • 1500 N

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31 mark

The medieval war machine shown below launches a stone projectile when the cable is released.

q23_moments_aqa-as-physics-mcq

What is the tension T in the cable in the position shown?

  • 2600 N

  • 3100 N

  • 3700 N

  • 800 N

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41 mark

The diagram below represents the arm of a crane lifting a 100 kN load. The arm has a mass of 8000 kg and a machine produces a reaction force F of 5 m from the bottom of the arm. The crane arm is uniform and in equilibrium.

q24_moments_aqa-as-physics-mcq

What is the value of F?

  • 54 MN

  • 52 MN

  • 2.9 kN 

  • 2.9 MN

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51 mark

The diagram below shows an irregular object supported on two springs. The spring on the left has a spring constant of k1 and a load of 20 N acts 0.50 m from this spring and 0.25 m from the spring on the right.

When the object is placed on the bottom of the springs, they each extend by the same amount.

q25_moments_aqa-as-physics-mcq

If the object is to be horizontal, what is the value of the spring constant for the spring on the right?

  • 0.5 k1

  • 5 k1

  • 2 k1

  • k1

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61 mark

A triangular object with a base diameter of 1m below is to be tilted until it falls over. The arrow drawn is the point at which the centre of mass of the cone acts.

q26_moments_aqa-as-physics-mcq

What height will the highest point on the base be just before the object falls over?

  • 34 cm

  • 91 cm

  • 64 cm

  • 94 cm

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71 mark

A car is driving up a uniform beam, of length 12 m. The car has a mass of 1000 kg and the beam has a mass of 200 kg. 

q27_moments_aqa-as-physics-mcq

How far along the beam beyond the pivot point can the car go just before the beam topples?

  • 0.4 m

  • 0.6 m

  • 0.8 m

  • 1.0 m

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81 mark

The diagram shows a child’s balancing game.

q28_moments_aqa-as-physics-mcq

The wooden rod is uniform and all the rings are of equal mass. Two rings are hung on peg 14, one on peg 2 and one on peg 11.

On which hook must a fourth ring be hung in order to balance the rod?

  • 2

  • 7

  • 5

  • 4

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91 mark

A uniform rod with a rubber handle and wooden section is made to balance on a pivot as shown below.

q29_moments_aqa-as-physics-mcq

What is the ratio fraction numerator d e n s i t y blank o f blank r u b b e r blank left parenthesis rho subscript r right parenthesis over denominator d e n s i t y blank o f blank w o o d blank left parenthesis rho subscript w right parenthesis end fraction ?

  • 0.2

  • 5.9

  • 3.1

  • 9.6

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101 mark

The diagram below four tangential forces applies to a circular object with radius r.

q30_moments_aqa-as-physics-mcq

If the clockwise direction is taken as positive, what is the resultant moment acting on the object?

  • 64 r clockwise

  • 0 stationary

  • 12 r clockwise

  • 12 r anticlockwise

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11 mark

A force of 9.8 N is applied at one end of a uniform beam of mass 2 kg that balances in equilibrium.

q11_moments_aqa-as-physics-mcq

Which of the following corresponds to the correct value of the reaction R on the beam?

  • 9.8 N down

  • 9.8 N up

  • 26 N down

  • 26 N up

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21 mark

A load L of 5000 N is placed on a horizontal beam between two boxes A and B. The beam itself exerts a force of 10 kN at its centre of mass.

The two reaction forces from the boxes are R1 and R2.

q12_moments_aqa-as-physics-mcq

Which of the following corresponds to the correct value of R1?

  • 900 N

  • 6000 N

  • 9000 N

  • 16 500 N

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31 mark

The uniform bar of length 0.60 m has a weight of 12 N and is in equilibrium in the diagram below. There is a hinge on the far right of the bar.

q13_moments_aqa-as-physics-mcq

What is the reading on the Newtonmeter?

  • 7 N

  • 9 N

  • 15 N

  • 96 N

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41 mark

The wall hook shown has a weight of 50 N attached to the end.

q14_moments_aqa-as-physics-mcq

What is the moment on the point of attachment to the base?

  • 1 N m

  • 1.25 N m

  • 2.5 N m

  • 5 N m

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51 mark

A door handle in the diagram below has a length 10 cm requires a force of 20 N to turn it.

q15_moments_aqa-as-physics-mcq

If the handle breaks and the door must be opened using the axle of the handle, with a diameter of 0.5 cm, how much force is needed?

  • 4 N

  • 8 N

  • 40 N

  • 400 N

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61 mark

A load L is placed on a horizontal beam balanced by boxes A and B. The beam has a mass mg.

q16_moments_aqa-as-physics-mcq

If load L is moved from box A towards box B, which of the following statements is true?

  • R1 increases and R2 decreases

  • R1 decreases and R2 increases

  • R1 = R2 throughout

  • Cannot tell without further data

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71 mark

A car bonnet, represented by QP, of mass 12 kg is pivoted at P. Its weight acts at G where QG = GP = 2.0 m.

q17_moments_aqa-as-physics-mcq

What force, F, acting perpendicular to QP as shown, is required to hold the bonnet at 40° to the horizontal?

  • 45 N

  • 59 N

  • 21 N

  • 120 N

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81 mark

A car wheel nut can be loosened by applying a force of 310 N on the end of a bar of length 0.7 m as in X. A car mechanic is capable of applying forces of 650 N simultaneously in opposite directions on the ends of a wheel wrench as in Y.

q18_moments_aqa-as-physics-mcq

What is the minimum length l of the wrench which would be needed for him to loosen the nut?

  • 0.17 m

  • 0.33 m

  • 3.00 m

  • 6.00 m

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91 mark

The diagram shows a uniform beam of weight 2.5 N and length of 150 cm is pivoted 32 cm from one end for use as a simple balance.

q19_moments_aqa-as-physics-mcq

A rock is placed at the end of the beam. The beam moves to a steady horizontal position when a weight of 7.1 N is added at a distance of 80 cm from the pivot as shown.

What is the weight of the rock?

  • 0.042 N

  • 18 N

  • 21 N

  • 24 N

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101 mark

An object, made from two equal masses joined by a light rod, falls with uniform speed through air. The rod remains horizontal.

Which statement about this system is incorrect?

  • it is in equilibrium because it is falling steadily

  • it is in equilibrium because the masses are equal

  • it is in equilibrium because it is the clockwise and anticlockwise moments are equal

  • it is in equilibrium because it has a resultant force

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