Quiz  /  Work Power and Energy Class 9 MCQ Questions With Answers

  • 1. 
    Check all of the things that can affect power

  • Work
  • Time
  • Force
  • All of above

  • 2. 
    When you rub your hands together on a cold day, you use friction to convert

  • Mechanical energy into thermal energy
  • Thermal energy into nuclear energy
  • Chemical energy into mechanical energy.
  • Electrical energy into thermal energy

  • 3. 
    A weightlifter lifts two 300 newton weights 1.5 meters off the ground. How much work has she done?

  • 600 J
  • 450 J
  • 900 J
  • 1200 J

  • 4. 
    You do 90 joules of work in 30 seconds. How much power have you generated?

  • 30 watts
  • 3 watts
  • 120 watts
  • 270 watts

  • 5. 
    At which point on the roller coaster is the kinetic energy at its maximum?

  • A
  • B
  • C
  • D

  • 6. 
    The amount by which a machine multiplies input force is known as the

  • work.
  • power.
  • output force.
  • mechanical advantage.

  • 7. 
    A student with a mass of 62 kg walks up a flight of stairs with a height of 3.4 meters. How can he decrease his power?

  • walk slower
  • walk faster
  • carry his friends books
  • All of above

  • 8. 
    Simple machines make work easier by increasing what?

  • The distance over which work is done
  • The force needed to do work
  • The time required to do work
  • The acceleration of a massive object

  • 9. 
    This is energy that is stored for later use.

  • kinetic energy
  • potential energy
  • mechanical energy
  • radiant energy

  • 10. 
    What type of simple machine is a bike pedal?

  • Inclined Plane
  • Pulley
  • Wedge
  • Lever

  • 11. 
    Light is an example of _________

  • thermal energy
  • radiant energy
  • mechanical energy
  • nuclear energy

  • 12. 
    How high up is a 3200-kg plane if it has 960000 J of potential energy?

  • 10 m
  • 30 m
  • 307200000 m
  • 300 m

  • 13. 
    Where is the roller coaster gaining potential energy?

  • A to B
  • B to C
  • C to D
  • The roller coaster is always losing potential energy

  • 14. 
    What effect do external forces like an applied force, friction force, or drag force have?

  • They have no effect on a system's mechanical energy.
  • They convert kinetic energy into potential energy.
  • They convert potential energy into kinetic energy.
  • They convert between mechanical energy and other forms of energy to change the total mechanical energy of the system.

  • 15. 
    If there is no friction on this track, at which point would the coaster have the most kinetic energy?

  • A
  • B
  • C
  • D

  • 16. 
    A block starts at rest at point P at the top of a ramp which is height h above the ground. The block slides down one side and up the other, stopping at a point less than h above the ground.

  • The block did not go as high on the other side because gravity pulls down.
  • The block did not go as high on the other side because potential energy always has to decrease.
  • The block did not go as high on the other side because work from friction made the mechanical energy less.
  • The situation as described is impossible to happen.

  • 17. 
    The energy of movement is...?

  • Kinetic
  • Potential

  • 18. 
    Which of the following is defined as work done per unit time?

  • energy
  • force
  • power
  • work

  • 19. 
    Two equal mass marbles are at the top of a ramp. One marble falls to the ground off the back while the other rolls down the ramp. What is true about the marbles when they reach the ground?

  • The marble that rolled down the ramp is moving faster than the marble that fell.
  • The marble that fell down the back of the ramp is moving faster than the marble that rolled.
  • The marble that rolled down the ramp is not moving when it reaches the ground.
  • The two marbles are moving with the same speed.

  • 20. 
    How does conservation of energy explain why something that is falling should speed up?

  • It gains kinetic energy because it gains potential energy.
  • It loses kinetic energy because no work was done on it.
  • It gains kinetic energy because it loses potential energy.
  • It loses kinetic energy because the Earth gains potential energy.

  • 21. 
    Which one is NOT a simple machine?

  • Lever
  • Gear
  • Wedge
  • Pulley

  • 22. 
    A cannon shoots a 1000 N stunt performer 100 m. How much work is done on the performer?

  • 100,000 J
  • 10,000 J
  • 10 J
  • 1,000,000 J

  • 23. 
    Kinetic energy is associated with ---.

  • speed
  • position
  • direction
  • temperature
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