﻿ A horizontal platform is rotating with uniform angular veloc

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## NEET Physics Solved Question Paper 2005

#### Multiple Choice Questions

1. 'Parsec' is the unit of'
• time

• distance

• frequency

• angular acceleration

2.

In the figure, the position-time graph of a particle of mass 0.1 kg is shown. The impulse at t = 2 sec is

• 0.2 kg m sec-1

• - 0.2 kg m sec-1

• 0.1 kg m sec-1

• - 0.4 kg m sec-1

3.

The pressure exerted by an electromagnetic wave of intensity I ( watt/m2 ) on a nonreflecting surface is [ c is the velocity of light ]

• Ic

• Ic2

• I/c

• I/c2

4.

A block of mass 10 kg is moving in x-direction with a constant speed of 10 m/sec. It is subjected to a retarding force F = -0.1 x joule/meter during its travel from x = 20 meter to x = 30 meter. Its final kinetic energy will be

• 475 joule

• 450 joule

• 275 joule

• 250 joule

5.

The condition for a uniform spherical mass m of radius r to be a black hole is [ G = gravitational constant and g = acceleration due to gravity ]

6.

When a ball is thrown up vertically with velocity  vo, it reaches a maximum height of h. If one wishes triple the maximum height then the ball should be thrown with velocity

• $\sqrt{3}$ vo

• 3vo

• 9vo

• 3/2 vo

7.

A solid sphere is rolling on a frictionless surface, show in figure with a translational velocity v m/s. If it is to climb the inclined surface then v should be

• ≥ $\sqrt{10}{7\mathrm{gh}}}$

• ≥ $\sqrt{2\mathrm{gh}}$

• 2gh

• 10/7 gh

# 8.A horizontal platform is rotating with uniform angular velocity around the vertical axis passing through its centre. At some instant of time a viscous fluid of mass 'm' is dropped at the centre and is allowed to spread out and finally fall. The angular velocity during this perioddecreases continuously decreases initially and increases again remains unaltered increases continuously

B.

decreases initially and increases again

According to law of conservation of momentum

Iω = consant

I = moment of inertia

ω = angular speed

When viscous fluid of mass m is dropped and start spreading out then its moment of inertia increases and angular velocity decreases. But when it start falling then its moment of inertia again starts decreasing and angular velocity increases.

9.

A ladder is leaned against a smooth wall and  it is allowed to slip on a frictionless floor. Which figure represents trace of its centre of mass.

10.

A person is standing in an elevator. In which situation he finds his weight less?

• When the elevator moves upward with constant acceleration

• When the elevator moves downward with constant acceleration

• When the elevator moves upward with uniform velocity

• When the elevator moves downward with uniform velocity