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DP IB Physics: SL

Topic Questions

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2.2 Forces

Question 1

Marks: 1

A frictionless spring-operated latched is fitted to a door. 

2-2-sl-mcq-hard-q1_1-phy

When the latch is pushed in, the spring compresses.

When the latch is released, which of the following best represents how acceleration a of the latch varies with the distance x it moves before stopping? 

  • 2-2-sl-mcq-hard-q1_2a-phy

  • 2-2-sl-mcq-hard-q1_2b-phy

  • 2-2-sl-mcq-hard-q1_2c-phy

  • 2-2-sl-mcq-hard-q1_2d-phy

Choose your answer
  

Question 2

Marks: 1

Elaborate chandeliers can be modelled as layers of hanging bars. The diagram shows one such model with a mass m suspended from two bars of negligible mass, connected by five light strings. Each layer has N number of strings. 

2-2-sl-mcq-hard-q2-phy

Which expression gives the tension in any single string? 

  • fraction numerator m g over denominator N end fraction

  • fraction numerator m g over denominator N squared end fraction

  • N m g

  • left parenthesis N minus 1 right parenthesis m g

Choose your answer
  
Key Concepts
Free-Body Diagrams

Question 3

Marks: 1

Two blocks, one made of wood and the other of iron, are arranged at rest on the ground. 

2-2-sl-mcq-hard-q3-phy

Which of the following statements is correct? 

  • The force exerted by the ground on the iron block in (1) is greater than the force exerted by the ground on the wooden block in (2) because the iron block, being denser than the wooden block, exerts more force on the ground. 

  • The force exerted by the wooden block on the iron block in (1) is equal to that exerted by the iron block on the wooden block in (2) by virtue of Newton's third law. 

  • The force exerted by the iron block on the wooden block in (1) is greater than that exerted by the wooden block on the iron block in (2). 

  • The force exerted by the wooden block on the iron block is equal to the weight of the wooden block in (1) while the force exerted by the iron block on the wooden block is equal to the weight of the iron block in (2). 

Choose your answer
  

Question 4

Marks: 1

A child of mass m sits in a car seat which is accelerating horizontally at 0.2g, where g is the acceleration due to gravity. 

What is the magnitude of the total force exerted by the car seat on the child? 

  • m g

  • square root of m g end root

  • square root of 0.2 end root m g

  • square root of 1.04 end root m g

Choose your answer
  

Question 5

Marks: 1

The following scenarios describe specific types of motion: 

  1. A diver equipped so that they remain at constant depth below the water surface without any effort on their part
  2. An athlete clearing the bar in a high jump
  3. A parachutist descending at terminal velocity with the parachute fully open

In which of the scenarios does the person concerned experience 'weightlessness'? 

  • I only 

  • II only 

  • II and III only

  • I, II and III

Choose your answer
  

Question 6

Marks: 1

A pendulum bob hangs from the ceiling in a carriage in a train and is just above a certain mark on the floor when the train is at rest. When the train is moving with a constant velocity forward, which statement best outlines the position of the bob? 

  • The bob is behind the mark, so that the pendulum thread is along the resultant of the forces due to the motion of the train and gravity. 

  • The bob remains over the mark because the force due to the motion of the train is balanced by the reaction of the thread on the support. 

  • The bob oscillates about the mark because of the unbalanced force due to the motion of the train. 

  • The bob remains over the mark because the motion of the train produces no additional force on the bob. 

Choose your answer
  

Question 7

Marks: 1

Two masses m and nm, where n > 1, are joined by a light string which passes over a frictionless pulley. The acceleration of free fall is g

2-2-sl-mcq-hard-q7-phy

What is the acceleration of the masses a and the tension in the string T

 

a

T

A.

fraction numerator n minus 1 over denominator n plus 1 end fraction

m g open parentheses fraction numerator n minus 1 over denominator n plus 1 end fraction close parentheses

B.

g left parenthesis n plus 1 right parenthesis

m g open parentheses fraction numerator n minus 1 over denominator n plus 1 end fraction minus 1 close parentheses

C.

fraction numerator g left parenthesis n minus 1 right parenthesis over denominator n plus 1 end fraction

m g open parentheses fraction numerator n minus 1 over denominator n plus 1 end fraction plus 1 close parentheses

D.

fraction numerator g left parenthesis n plus 1 right parenthesis over denominator n minus 1 end fraction

m g open parentheses fraction numerator n plus 1 over denominator n minus 1 end fraction plus 1 close parentheses

    Choose your answer
      

    Question 8

    Marks: 1

    Two bodies, X and Y, having masses mX and mY respectively, exert forces on each other and have no external forces acting on them. The force acting on X is F, which gives X an acceleration aX.

    What is the magnitude of the force on Y and its acceleration?

     

    Magnitude of force on Y

    Acceleration of Y

    A.

    m subscript Y over m subscript X F

    a

    B.

    F

    m subscript Y over m subscript X a

    C.

    m subscript X over m subscript Y F

    a

    D.

    F

    m subscript X over m subscript Y a

      Choose your answer
        

      Question 9

      Marks: 1

      Two blocks with mass 5m and 3m are pushed along a smooth horizontal surface by an applied force F.

      2-2-sl-mcq-hard-q9-phy

      What is the magnitude of the force exerted between the blocks? 

      • F

      • 2 over 8 F

      • 3 over 8 F

      • 8 over 3 F

      Choose your answer
        

      Question 10

      Marks: 1

      Forces act in a variety of situations described below: 

      1. The centripetal force holding a satellite in orbit round the Earth and the weight of the satellite 
      2. Repulsive forces experienced by anti-parallel current-carrying conductors 
      3. Attractive forces between two gas molecules passing close to each other
      4. Attractive forces between the nucleus and orbiting electrons in an atom

      Which of the situations describe pairs of forces as required by Newton's third law? 

      • I and II only

      • II and III only 

      • I, II and IV only

      • II, III and IV only

      Choose your answer