# Multiple Choice Questions (MCQ) on Mechanics – Set 2

Multiple Choice Questions (MCQ) on Mechanics – Set 2

An iron ball and a cotton ball of same mass are thrown from a height ‘h’ in air. Then

(a) The cotton ball will reach the ground first

(b) the cotton ball will reach the ground first

(c) both balls reach the ground at the same time

(d) none of these

(Ans:c)

Acceleration due to gravity

(a) same at all places

(b) more at the equator of the earth than at the poles

(c) decreasing with altitude

(d) All are correct

(Ans:c)

A man moving in an accelerated train on horizontal tracks feels that his weight has/is

(a) decreased

(b) increased

(c) zero

(d) same

(Ans:d)

The numbers of independent equations available from static equations of equilibrium for plane problems are

(a) 3

(b) 6

(c) 12

(d) 9

(Ans:a)

According to the law of equilibrium, two forces are said to be in equilibrium only if they are

(a) equal in magnitude and opposite in direction

(b) opposite in direction

(c) collinear in action

(d) both (a) and (b)

(Ans:d)

A block slides down a smooth inclined plane at 30° in time from the top. If an identical block is released from the same point, falling freely to the ground, then it will reach in time

(a) t/2

(b) t/3

(c) t/4

(d) t

(Ans:a)

A zero torque acting on a system results in conservation of

(a) angular momentum

(b) linear momentum

(c) angular velocity

(d) energy

(Ans:a)

A railway train of 200m long passes over a 600m long bridge. If the train is moving at 10m/s, the time taken to cross the bridge

(a) 60s

(b) 90s

(c) 80s

(d) 100s

(Ans:c)

Two bodies of masses m1 and m2 are dropped from the same height. The ratio of their momentum at the ground is

(a) m1/m2

(b) m2/m1

(c) (m1/m2)^1/2

(d) (m2/m1)^1/2

(Ans:a)

A body of weight W is placed on an inclined plane. The angle made by the inclined plane with horizontal, when the body is on the point of moving down is called

(a) angle of inclination

(b) angle of repose

(c) angle of friction

(d) angle of limiting friction

(Ans:b)

The statement – “If three forces acting at a point can be represented in magnitude and directions by the sides of a triangle taken in order, the forces are in equilibrium” – is known as

(a) Lami’s theorem

(b) Law of Polygon of forces

(c) Law of triangle of forces

(d) Newton’s law of forces

(Ans:c)

If a body is moving in a straight line, the motion of the body is called

(a) rectilinear

(b) rotational

(c) curvilinear

(d) helical

(Ans:a)

Free body diagram of a body in a force system is

(a) completely isolated from the system

(b) incompletely isolated from the system

(c) completely attached to the system

(d) incompletely attached to the system

(Ans:a)

Centroid of a body is its

(a) geometrical concentration

(b) mass concentration

(c) weight concentration

(d) density concentration

(Ans:a)

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

(a) uniform speed

(b) an acceleration

(c) some linear acceleration

(d) retardation

(Ans:b)

When a body falls freely under gravity it possesses

(a) maximum weight

(b) minimum weight

(c) no weight

(d) a weight depending upon velocity

(Ans:c)

When a body slides down an inclined surface, inclined at an angle β, the acceleration ‘a’ of the body is given by

(a) a = g

(b) a = g sinβ

(c) a = g cosβ

(d) a = g tanβ

(Ans:b)