# AFCAT: Physics MCQs (Practice_Test 18 of 35)

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If the linear density of a rod of length 3 m varies as l = 2 + x, then the position of the centre of gravity of the rod is

7/3 m

12/3 m

10/7 m

9/7 m

The maximum velocity of a simple harmonic motion represented by y = 3 sin (100t + p/6) is given by

300

3p/6

100

p/6

A simple pendulum of length L is set up inside a wagon sliding down a smooth inclined plane of inclination with the horizontal. The period of oscillation recorded by an observer inside will be

2p (L/g cos q) ½

2p (L/g sin q) ½

2p (L/g) ½

2p (L cos q) =

In an elastic one-dimensional collision between two particles, the relative velocity of approach before collision is

greater than the relative velocity of separation after collision

less than the relative velocity of separation after collision

equal to the relative velocity of separation after collision

less than the relative velocity of separation if the incoming particles heavier than the target particle.

Annihilation of 1 gm of matter could theoretically yield electric energy of the order of

1032 eV

1013 eV

103 eV

l eV

The rest mass of the photon of frequency v is

zero

hv

hv/c2

infinite

In the case of a fluid, Bernoulli's theorem expresses the application of the principle of conservation of

linear momentum

energy

mass

angular momentum

Small droplets of 1iquid assume spherical shape because

energy due to surface tension is lowest for a sphere

energy due to surface tension is the highest for a sphere.

volume energy is the highest for a sphere

surface tension acts against the force of gravity