set 3 MCQ Questions & Answers Detailed Explanation

Question : 1

The sum of the change in kinetic and potential energy is always

a) Negative

b) Positive

c) Zero

d) None of the above

Question : 2

The following four wires are made of the same material. Which of these will have the largest extension when the same tension is applied ?

a) length = 200 cm, diameter = 2 mm

b) length = 50 cm, diameter = 0.5 mm

c) length = 100 cm, diameter = 1 mm

d) length = 300 cm, diameter = 3 mm

Question : 3

As the train starts moving, the head of the passenger sitting inside leans backward because of

a) Moment of Inertia

b) Inertia of Motion

c) Inertia of Rest

d) Conservation of Mass

Question : 4

The centre of mass of triangle shown in figure has coordinates

a) $x = b/3, y = h/3$

b) $x = b/2, y = h/2$

c) $x = h/2, y = b/2$

d) $x = h/3, y = b/3$

Question : 5

Regarding mechanical energy, which of the following statements is/are correct?

1. Kinetic energy of a body depends upon the direction of motion.
2. When a body falls freely, its P.E. is converted into K.E.
3. A body at rest may possess P.E.

a) 2 only

b) 1 and 2

c) 2 and 3

d) 3 only

Question : 6

How much time will it take to perform 440 J of work at a rate of 11 W?

a) 30 s

b) 40 s

c) 50 s

d) 20 s