Basic Chemical Engineering Multiple Choice Questions & Answers (MCQs) on “Potential Energy and Kinetic Energy”.

**1. What is the change potential energy of a stone of mass 5 Kg that falls from a cliff 10 m high?**

a) 5 J

b) 50 J

c) 500 J

d) 5000 J

**Answer: c**

Clarification: PE = 5*10*10 = 500 J.

**2. What is the change in potential energy of a stone of mass 1 Kg thrown up with a velocity 10 m/s and comes down?**

a) 0

b) 10 J

c) 100 J

d) 500 J

**Answer: a**

Clarification: Since the stone comes down to its initial position, its potential energy does not change.

**3. A fluid in supplied to a cliff 10 m high, what is the change in specific potential energy of fluid?**

a) 10 J/Kg

b) 100 J/Kg

c) 200 J/Kg

d) 500 J/Kg

**Answer: b**

Clarification: Change in specific potential energy = 10*10 = 100 J/Kg.

**4. A fluid is supplied to a cliff 20 m high and comes down by 5 m, what is the change in specific potential energy of fluid?**

a) 100 J/Kg

b) 150 J/Kg

c) 200 J/Kg

d) 250 J/Kg

**Answer: b**

Clarification: Change in specific potential energy = 10*(20 – 5) = 150 J/Kg.

**5. A ball is thrown up and someone catches it on the cliff, what is the change in potential energy?**

a) Positive

b) Negative

c) Zero

d) Cannot say

**Answer: a**

Clarification: Change in potential energy will be positive as the change in kinetic energy will be negative.

**6. What is the kinetic energy of an object of mass 10 Kg moving with velocity 2 m/s?**

a) 10 J

b) 20 J

c) 40 J

d) 50 J

**Answer: b**

Clarification: KE = ½*10*2^{2} = 20 J.

**7. What is the kinetic energy of an object of mass 2 Kg and velocity 5 m/s?**

a) 20 J

b) 25 J

c) 35 J

d) 50 J

**Answer: b**

Clarification: KE = ½*2*5^{2} = 25 J.

**8. What is the specific kinetic energy of a fluid flowing at rate 0.1 m ^{3}/s and 1 m diameter pipe?**

a) 0.008 J/Kg

b) 0.016 J/Kg

c) 0.028 J/Kg

d) 0.064 J/Kg

**Answer: a**

Clarification: v = 0.1/∏(0.5)^{2}, => specific KE = v^{2}/2 = 0.008 J/Kg.

**9. A stone is thrown up with a velocity and comes down, what is the change in kinetic energy of stone?**

a) Positive

b) Negative

c) Zero

d) Cannot say

**Answer: c**

Clarification: According to the conservation of energy, during a process change in total energy will always be zero, if the stone comes to the same level the change in potential energy becomes zero so the change in kinetic energy also becomes zero.

**10. A stone is released from a cliff and comes down, what is the change in kinetic energy of stone?**

a) Positive

b) Negative

c) Zero

d) Cannot say

**Answer: a**

Clarification: Since its velocity increases as it comes down, so a change in kinetic energy is positive.