# Mechanics (mass, Force, Acceleration, Work, Energy, Momentum, Velocity) - Category Wise Question And Answer Practice Test With Solutions

#### MECHANICS (MASS, FORCE, ACCELERATION, WORK, ENERGY, MOMENTUM, VELOCITY) PRACTICE TEST [5 - EXERCISES]

Question : 1

The number of significant figures in 0.00060 m is

a) 3

b) 2

c) 1

d) 4

According to rules of significant figures.

Question : 2

For a body falling freely under gravity from a height

a) both kinetic energy as well as potential energy go on increasing

b) only the kinetic energy goes on increasing

c) only the potential energy goes on increasing

d) the kinetic energy goes on increasing while potential energy goes on decreasing

Question : 3

A parrot is sitting on the floor of a closed glass cage which is in a boy’s hand. If the parrot starts flying with a constant speed, the boy will feel the weight of the cage as

a) increased

b) reduced

c) unchanged

d) nothing can be said

Question : 4 [CDS]

The pressure exerted on the ground by a man is greatest

a) when the stands with both foot flat on the ground

b) when the stands on the toes of one foot

c) when the lies down in the ground

d) all of the above yield the same pressure

Question : 5

A particle is projected at some angle from the surface of the planet. The motion of the particle is described by the equation; x = t, y = t - \$t^2\$ . Then match the following columns and select the correct answer using the codes given below the lists.

 Column I (Quantity) Column II (Magnitude only) A. velocity of projection 1. 1 B. acceleration 2. \$√2\$ C. time of flight 3. 2 D. maximum height attained 4. \$1/4\$
Choose the correct option from the codes given below:

a) A – 2 ; B – 3 ; C – 1 ; D – 4

b) A – 2 ; B – 1 ; C – 4 ; D – 3

c) A – 1 ; B – 2 ; C – 3 ; D – 4

d) A – 4 ; B – 3 ; C – 2 ; D – 1

A → (2) ; B → (3) ; C→ (1) ; D → (4)

Option: (A) Ux = \${dx}/{dt}\$ = 1 and Uy = \${dx}/{dt}\$ = 1 – 2t

∴ Ut=0 = √{U2x + y2y} + √{1+ 12}= √2 m/s.

Option: (B) ax = \${d^2 x}/{dt^2}\$ = 0

dy = \${d^2 y}/{dt^2}\$ = – 2

Option: (C) For the time of flight,

y = 0

or 0 = t – t2

∴ t = 1s.

Option: (D) For maximum height, t = \$1/2\$ s.

∴ H = t – t2 = \$1/2\$ - \$(1/2)^2\$ = \$1/4\$ m.