1. A machine having an efficiency greater than 50%, is known as ?

reversible machine

a non-reversible machine

neither reversible nor non-reversible machine

ideal machine

Answer: reversible machine

Explanation:


2. The mechanical advantage of a lifting machine is the ratio of ?

distance moved by effort to the distance moved by load

load lifted to the effort applied

output to the input

all of the above

Answer: load lifted to the effort applied

Explanation:


3. Which of the following statement is correct ?

The kinetic energy of a body during impact remains constant

The kinetic energy of a body before impact is equal to the kinetic energy of a body after impact

The kinetic energy of a body before impact is less than the kinetic energy of a body after impact

The kinetic energy of a body before impact is more than the kinetic energy of a body after impact

Answer: The kinetic energy of a body before impact is more than the kinetic energy of a body after impact

Explanation:


4. The law of motion involved in the recoil of gun is ?

Newton's first law of motion

Newton's second law of motion

Newton's third law of motion

none of these

Answer: Newton's third law of motion

Explanation:


5. One watt is equal to ?

0.1 joule/s

1 joule/s

10 joules/s

100 joules/s

Answer: 1 joule/s

Explanation:


6. One kg force is equal to ?

7.8 N

8.9 N

9.8 N

12N

Answer: 9.8 N

Explanation:


7. The three forces of 100 N, 200 N and 300 N have their lines of action parallel to each other but act in the opposite directions. These forces are known as ?

coplaner concurrent forces

coplaner non-concurrent forces

like parallel forces

unlike parallel forces

Answer: unlike parallel forces

Explanation:


8. The friction experienced by a body, when at rest, is known as ?

static friction

dynamic friction

limiting friction

coefficient of friction

Answer: static friction

Explanation:


9. When a rigid body is suspended vertically, and it oscillates with a small amplitude under the action of the force of gravity, the body is known as ?

simple pendulum

compound pendulum

torsional pendulum

second's pendulum

Answer: compound pendulum

Explanation:


10. The unit of force in S.I. system of units is ?

dyne

kilogram

newton

watt

Answer: kilogram

Explanation: