Physics Crash Course NDA & NA EE>Chapter 8 - Rotational Mechanics>Exercise 1>Q 16

EASY

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IMPORTANT

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Assertion $(A) :$ If the ice on the polar caps of the earth melts, then length of the day will increase.

Reason $(R) :$ Moment of inertia of earth increases, as ice on polar caps melts.

The correct answer is

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Important Questions on Rotational Mechanics

EASY

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IMPORTANT

Physics Crash Course NDA & NA EE>Chapter 8 - Rotational Mechanics>Exercise 1>Q 1

Torque per unit moment of inertia is equal to

EASY

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IMPORTANT

Physics Crash Course NDA & NA EE>Chapter 8 - Rotational Mechanics>Exercise 1>Q 2

A particle of mass

M

and radius of gyration

K

is rotating with angular acceleration

α

. The torque acting on the particle is,

EASY

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IMPORTANT

Physics Crash Course NDA & NA EE>Chapter 8 - Rotational Mechanics>Exercise 1>Q 3

A force

\vec{F} = 4 \hat{i} - 5 \hat{j} + 3 \hat{k}

is acting at a point

{\vec{r}}_{1} = \hat{i} + 2 \hat{j} + 3 \hat{k} .

The torque acting about a point

{\vec{r}}_{2} = 3 \hat{i} - 2 \hat{j} - 3 \hat{k}

is,

EASY

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IMPORTANT

Physics Crash Course NDA & NA EE>Chapter 8 - Rotational Mechanics>Exercise 1>Q 4

A rod of weight

W

is supported by two parallel knife edges

A

and

B

and is in equilibrium in a horizontal position. The knives are at a distance

d

from each other. The centre of mass of the rod is at distance

x

from

A

. The normal reaction on

A

is

EASY

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IMPORTANT

Physics Crash Course NDA & NA EE>Chapter 8 - Rotational Mechanics>Exercise 1>Q 5

A light rope is wound around a hollow cylinder of mass

4 kg

and radius

40 cm

. If the rope is pulled with a force of

40 N

, its angular acceleration is______.

EASY

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IMPORTANT

Physics Crash Course NDA & NA EE>Chapter 8 - Rotational Mechanics>Exercise 1>Q 6

A door

1.6 m

wide requires a minimum force of

1 N

to be applied at the free end to open or close it. The minimum force that is required at a point

0.4 m

away from the hinges for opening or closing the door is

EASY

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IMPORTANT

Physics Crash Course NDA & NA EE>Chapter 8 - Rotational Mechanics>Exercise 1>Q 7

The quantity not involved directly in rotational motion of the body is

EASY

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IMPORTANT

Physics Crash Course NDA & NA EE>Chapter 8 - Rotational Mechanics>Exercise 1>Q 8

Essential characteristic of equilibrium is