# Practice Test: Question Set - 20

**1. A glass ball is shot to hit a wall from a point on a smooth floor. If the ball returns back to the point of projection in twice the time taken in reaching the wall, the coefficient of restitution between the glass ball and the wall is**

- (A) 0.25

- (B) 0.33

- (C) 0.40

- (D) 0.50

**2. Power can be expressed as**

- (A) Work/energy

- (B) Work/time

- (C) Work × time

- (D) Work/distance

**3. A system of coplanar forces is in equilibrium when**

- (A) Force polygon closes

- (B) Funicular polygon closes

- (C) Both force polygon" and funicular
polygon close

- (D) All the forces are concurrent

**4. The practical units of work, is**

- (A) Erg

- (B) Joule

- (C) Newton

- (D) Dyne

**5. For a simple pendulum, the period of one oscillation is**

- (A) 2π √

*(l*/2

*g)*

- (B) 2π √

*(*2

*g*/

*l)*

- (C) 2π √

*(l*/

*g)*

- (D) 2π √

*(g*/2

*l)*

**6. Which of the following is a scalar quantity?**

- (A) Energy

- (B) Momentum

- (C) Torque

- (D) Impulse

**7. The gravitational force makes a satellite go round the earth in a circular orbit, if it is projected with an initial velocity of**

- (A) 8.04 km/sec
at a height of 285 km

- (B) 11.11 km/sec
at a height of 37,400 km

- (C) 11.26
km/sec, the satellite escapes the pull of the earth

- (D) All the
above

**8. The apparent weight of a man in a moving lift is less than his real weight when it is going down with**

- (A) Uniform
speed

- (B) An
acceleration

- (C) Linear
momentum

- (D) Retardation

**9. The torque produced by a force depends on**

**(i) The magnitude of the force**

**(ii) The direction of the force**

**(iii) The point of application of the force relative to origin**

**The correct answer is**

- (A) Only (i)

- (B) Both (i) and (ii)

- (C) Both (i) and (iii)

- (D) All (i), (ii) and (iii)

**10. Two parallel forces 20 kg and 15 kg act. In order that the distance of the resultant from 20 kg force may be the same as that of the former resultant was from 15 kg, the 20 kg force is diminished by**

- (A) 5.5 kg

- (B) 6.25 kg

- (C) 8.75 kg

- (D) 10.5 kg

**11. If the linear velocity of a point on the rim of a wheel of 10 m diameter, is 50 m/sec, its angular velocity will be**

- (A) 20 rad/sec

- (B) 15 rad/sec

- (C) 10 rad/sec

- (D) 5 rad/sec

**12. A simple pendulum of length 1 has an energy**

*E*when its amplitude is*A*. If its amplitude is increased to 2*A*, the energy becomes- (A)

*E*

- (B)

*E*/2

- (C) 2

*E*

- (D) 4

*E*

**13. A projectile is fired at an angle ‘θ’ to the vertical. Its horizontal range will be maximum when ‘θ’ is**

- (A) 0°

- (B) 30°

- (C) 45°

- (D) 90°

**14. The resultant of the forces acting on a body will be zero if the body**

- (A) Rotates

- (B) Moves with
variable velocity in a straight line

- (C) Moves along
a curved path

- (D) Does not
move at all

**15. The ratio of the speed of a rolling cylinder to the speed of sliding cylinder is**

- (A) Less than 1

- (B) Equal to 1

- (C) Between 1 and 2

- (D) Greater than 2

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