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DP IB Physics: SL

Topic Questions

Home / IB / Physics: SL / DP / Topic Questions / 2. Mechanics / 2.3 Work, Energy & Power / Multiple Choice


2.3 Work, Energy & Power

Question 1

Marks: 1

A trampolinist bounces up and down on their trampoline.

Which row states the energy transformations that take place in the system when the trampolinist bounces down on the trampoline and back up again. Assume that air resistance is negligible.

  • Gravitational potential → elastic potential → kinetic →  elastic potential → gravitational potential

  • Gravitational potential → kinetic → elastic potential → kinetic → gravitational potential 

  • Kinetic → gravitational potential → elastic potential → gravitational potential → kinetic 

  • Gravitational potential → kinetic → elastic potential → gravitational potential 

Choose your answer
  

Question 2

Marks: 1

An object falls from rest from a height h close to the surface of the Moon. The Moon has no atmosphere.

When the object has fallen to height h over 3 above the surface, what is

                                    fraction numerator g r a v i t a t i o n a l space p o t e n t i a l space e n e r g y space o f space t h e space o b j e c t space a t space h over denominator k i n e t i c space e n e r g y space o f space t h e space o b j e c t space a t space begin display style h over 3 end style end fraction

  • 3

  • 1 third

  • 2 over 3

  • 3 over 2

Choose your answer
  

Question 3

Marks: 1

A horizontal spring of spring constant k and negligible mass is compressed through a distance y from its equilibrium length. An object of mass m that moves on a frictionless surface is placed at the end of the spring. The spring is released at speed  v and returns to its equilibrium length.q13_work-energy-power_ib-sl-physics-mcq

What is the value of y?

  • square root of m over k end rootv

  • square root of k over m end rootv

  • m over kv

  • k over mv

Choose your answer
  

Question 4

Marks: 1

A student states three scenarios in which she thinks no work is done on an object.

  1. A pulling force on a sledge being pulled at an angle.
  2. A charged particle in a magnetic field.
  3. A drag force acting a car.

Which of the above scenarios is / are correct?

  • I and II only

  • I and III only

  • II only

  • All three

Choose your answer
  
Key Concepts
Work Done

Question 5

Marks: 1

The power generated by the nuclear reactions in the core of the reactor is 35 GW.

If the efficiency of the power station is 60%, how much power goes into producing wasted energy?

  • 35 GW

  • 21 GW

  • 14 GW

  • 18 GW

Choose your answer
  
Key Concepts
Efficiency
Power

Question 6

Marks: 1

A mass with speed v travels up to point X then down to Y.

q16_work-energy-power_ib-sl-physics-mcq

Assuming air resistance is negligible, what is v of the mass at point Y?

  • square root of fraction numerator 2 g h over denominator 5 end fraction end root

  • 2square root of fraction numerator g h over denominator 5 end fraction end root

  • 4square root of fraction numerator g h over denominator 5 end fraction end root

  • square root of fraction numerator 3 g h over denominator 5 end fraction end root

Choose your answer
  

Question 7

Marks: 1

A student of mass 50 kg climbs a vertical ladder 4.0 m tall in a time of 8.0 s. What is the power developed by the student against gravity?

  • 25 W

  • 200 W

  • 1000 W

  • 250 W

Choose your answer
  
Key Concepts
Power

Question 8

Marks: 1

The efficiency of an electric motor is 80 %. When lifting a body, the amount of energy wasted is E subscript w. What is the useful work done by the motor?

  • E subscript w over 4

  • E subscript W

  • 0.8 E subscript W

  • 0.4E subscript w

Choose your answer
  
Key Concepts
Efficiency

Question 9

Marks: 1

A lift is operated by an electric motor. It moves between the 21st and the 5th floor at a constant speed. One main energy transformation during this journey is:

  • Electric energy → Gravitational potential energy 

  • Gravitational potential energy → Kinetic energy

  • Electric energy → Thermal energy

  • Kinetic energy → Electric energy

Choose your answer
  

Question 10

Marks: 1

A spring of mass m and spring constant k rests on top of a vertical spring whose base is attached to the floor.

What is the energy stored by the spring?

  • fraction numerator m squared g squared over denominator 2 k end fraction

  • fraction numerator m squared g squared over denominator 2 k squared end fraction

  • fraction numerator m g over denominator 2 k end fraction

  • fraction numerator m g over denominator 2 end fraction

Choose your answer