Class 9 Science Work and Energy

Class 9 Science Work and Energy

 

Class 9 Science Work and Energy Fill in the blanks , Multiple Choice Question [mcq] and True false .

 

Fill in the Blanks

1. Work is said to be done when a ______ acts on an object and the object is displaced.
Answer: force

2. Work = ______ × displacement.
Answer: force

3. The SI unit of work is ______.
Answer: joule

4. One joule is the work done when a force of 1 ______ displaces an object by 1 meter.
Answer: newton

5. An object that can do work is said to possess ______.
Answer: energy

6. The energy possessed by a moving object is called ______ energy.
Answer: kinetic

7. The energy possessed by a body due to its position is called ______ energy.
Answer: potential

8. Kinetic energy = ½ × ______ × velocity²
Answer: mass

9. Potential energy = mass × ______ × height
Answer: gravity (or acceleration due to gravity)

10. Power = work done / ______
Answer: time

11. The SI unit of power is ______.
Answer: watt

12. 1 kilowatt = ______ watts
Answer: 1000

13. Energy can neither be created nor destroyed, it only gets ______ from one form to another.
Answer: transformed

14. Mechanical energy = kinetic energy + ______ energy
Answer: potential

15. When work is done against gravity, the object gains ______ energy.
Answer: potential

 

Multiple Choice Questions (MCQs)

 

1. What is the SI unit of energy?
a) Newton
b) Joule
c) Watt
d) Calorie
Answer: b) Joule

 

2. Work is done when:
a) Force is applied
b) Object moves
c) Both force is applied and object moves
d) No movement
Answer: c) Both force is applied and object moves

 

3. If displacement is zero, work done is:
a) Maximum
b) Positive
c) Negative
d) Zero
Answer: d) Zero

 

4. A ball rolling on the ground possesses:
a) Heat energy
b) Sound energy
c) Potential energy
d) Kinetic energy
Answer: d) Kinetic energy

 

5. Which of the following is a form of mechanical energy?
a) Heat
b) Sound
c) Light
d) Potential energy
Answer: d) Potential energy

 

6. A body of mass m raised to height h has potential energy of:
a) mh
b) mgh
c) mv²
d) m/h
Answer: b) mgh

 

7. Which energy is associated with motion?
a) Potential energy
b) Solar energy
c) Kinetic energy
d) Heat energy
Answer: c) Kinetic energy

 

8. A falling object gains:
a) Potential energy
b) Heat
c) Kinetic energy
d) Electrical energy
Answer: c) Kinetic energy

 

9. Power is the rate of:
a) Displacement
b) Force
c) Doing work
d) Speed
Answer: c) Doing work

 

10. 1 watt is equal to:
a) 1 J/min
b) 1 N/s
c) 1 J/s
d) 1 N·m
Answer: c) 1 J/s

 

11. Which of the following has energy stored due to its position?
a) Moving car
b) Stretched rubber band
c) Blowing wind
d) Burning candle
Answer: b) Stretched rubber band

 

12. In which case is no work done?
a) Lifting a box
b) Pushing a wall
c) Pulling a trolley
d) Kicking a ball
Answer: b) Pushing a wall

 

13. What does “work done is negative” mean?
a) Force and displacement are in same direction
b) No displacement
c) Force is opposite to displacement
d) Work is not done
Answer: c) Force is opposite to displacement

 

14. The law of conservation of energy states:
a) Energy disappears
b) Energy can be created
c) Energy is destroyed
d) Energy is conserved
Answer: d) Energy is conserved

 

15. The power of a machine that does 100 J work in 10 seconds is:
a) 1000 W
b) 10 W
c) 110 W
d) 5 W
Answer: b) 10 W

 

True or False

 

1. Energy is the capacity to do work. Answer: True

2. If there is no displacement, no work is done. Answer: True

3. Joule is the SI unit of power. Answer: False (Watt is)

4. A stretched rubber band has potential energy. Answer: True

5. The energy of a moving object is called potential energy. Answer: False (It’s kinetic energy)

6. Work can be both positive and negative. Answer: True

7. A person standing still with a heavy load is doing scientific work. Answer: False

8. Work done = energy transferred. Answer: True

9. Power is measured in newtons. Answer: False (Power is measured in watts)

10. 1 kilojoule = 1000 joules. Answer: True

11. Mechanical energy = Kinetic + Thermal energy. Answer: False (It’s Kinetic + Potential)

12. Energy can be created during transformation. Answer: False

13. When velocity doubles, kinetic energy becomes four times. Answer: True

14. When an object is at rest, it always has kinetic energy. Answer: False

15. Work is done if force is applied but the object doesn’t move. Answer: False