Practice Test: Question Set - 21
1. If u1 and u2 are the velocities of two moving bodies in the same direction before impact and v1 and v2 are their velocities after impact, then coefficient of restitution is given by
- (A) (v1 - v2)/(u1 - u2)
- (B) (v₂ - v₁)/(u1 - u2)
- (C) (u1 - u2)/(v1 - v2)
- (D) (u₂ + u₁)/(v₂ + v₁)
2. Work done is said to be zero, when
- (A) Some
force acts on a body, but displacement is zero
- (B) No
force acts on a body but some displacement takes place
- (C) Either (A)
or (B)
- (D) None of the
above
3. The range of projectile on a downward inclined plane is ________ the range on upward inclined plane for the same velocity of projection and angle of projection.
- (A) Less than
- (B) More
than
- (C) Equal to
- (D) None of
These
4. The point, through which the whole weight of the body acts, irrespective of its position, is known as
- (A) Moment
of inertia
- (B) Center of gravity
- (C) Center of percussion
- (D) Center of mass
5. The total energy possessed by a system of moving bodies
- (A) Is
constant at every instant
- (B) Varies
from point to point
- (C) Is
maximum in the start and minimum at the end
- (D) Is
minimum in the start and maximum at the end
6. The acceleration of a body sliding down an inclined surface is
- (A) g sinθ
- (B) g cosθ
- (C) g tanθ
- (D) None of
these
7. A force while acting on a body may
- (A) Change
its motion
- (B) Balance the
forces, already acting on it
- (C) Give rise to
the internal stresses in it
- (D) All of these
8. A machine having an efficiency less than 50%, is known as
- (A) Reversible
machine
- (B) Non-reversible
machine
- (C) Neither
reversible nor non-reversible machine
- (D) Ideal
machine
9. Static friction is always __________ dynamic friction.
- (A) Equal to
- (B) Less than
- (C) Greater than
- (D) None of
these
10. In the shown figure, the tension (T) in the string will be
- (A) m₁. m₂. g/(m₁ + m₂)
- (B) 2m₁. m₂. g/(m₁ + m₂)
- (C) (m₁ +
m₂)/ m₁. m₂. g
- (D) (m₁ + m₂)/2m₁. m₂. g
11. A body of weight 'W' is required to move up on rough inclined plane whose angle of inclination with the horizontal is 'α'. The effort applied parallel to the plane is given by (where μ = tanφ = Coefficient of friction between the plane and the body.)
- (A) P = W tanα
- (B) P = W tan (α + φ)
- (C) P = W (sinα + μcosα)
- (D) P = W (cosα + μsinα)
12. A smooth cylinder lying on a __________ is in neutral equilibrium.
- (A) Curved
surface
- (B) Convex
surface
- (C) Horizontal
surface
- (D) None
of these
13. The unit of energy in S.I. units is
- (A) Dyne
- (B) Watt
- (C) kg-m
- (D) Joule
14. A ladder is resting on a rough ground and leaning against a smooth vertical wall. The force of friction will act
- (A) Downward at
its upper end
- (B) Upward
at its upper end
- (C) Zero
at its upper end
- (D) Perpendicular
to the wall at its upper end
15. The periodic time of one oscillation for a simple pendulum is (where l = Length of the pendulum.)
- (A) (1/2Ï€). √(l/g)
- (B) (1/2Ï€). √(g/l)
- (C) 2Ï€. √(l/g)
- (D) None of
these
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