Law of Conservation of Energy

Q. Energy is neither created nor destroyed.

1. False
2. True

Q.

How does potential energy increase with increase in height. What is the logic.

Q.

Which of the given statement is incorrect in regard to the law of conservation of energy?

1. Energy cannot be created

2. Energy cannot be transformed

3. Energy cannot be destroyed

4. Total energy always remains the same

Q. A 5000 kg rocket is set for vertical firing. The exhaust speed is 800 ms1. To give an initial upward acceleration of 20 ms2, the amount of gas ejected per second to supply the needed thrust will be (g= 10 ms2)

Q.

An object falls from a height h. When it has reaches a height of $h/2$, it will possess more potential and less kinetic energy.

1. True
2. False

Q. According to Vanka, what kind of a person is Konstantin Makarich? Do you justify Makarich’s decision to send Vanka away to Moscow? Why?

Q.

Morning breakfast gives 5000 cal to a 60 kg person. The efficiency of person is 30%. the height upto which the person can climb up by using energy obtained from breakfast is?

Ans 10.5 m

How?

Q.

A body is falling from a height $h$, after it has fallen from a height $h/2$, it will possess.

1. only potential energy

2. only kinetic energy

3. half potential energy and half kinetic energy

4. more kinetic and less potential energy

Q.

Write the names.

1. Energy of abody due to its motion.
2. Ability to do work.
3. Energy possessed by a body due to its height above the ground.
4. Appliance that changes sound energy into electrical energy.
5. Energy stored in a stretched spring.