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Which of the following is a result of mechanical weathering?

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Important Questions on Work, Energy and Power

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

A rod, of length

L

at room temperature and uniform area of cross section

A,

is made of a metal having coefficient of linear expansion

α / ° C

It is observed that an external compressive force

F

is applied on each of its ends, prevents any change in the length of the rod when its temperature rises by

∆ T K

Young's modulus,

Y

for this metal is:

EASY

Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

Starting from the center of the earth having radius,

R

, the variation of

g

(acceleration due to gravity) is shown by

EASY

Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

The potential energy of a system increases if work is done

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

At what height from the surface of earth the gravitation potential and the value of g are

- 5.4 \times 10^{7} J k g^{- 2}

and

6.0 m s^{- 2}

respectively? Take the radius of earth as

6400 km

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

An ideal gas is expanding such that

P T =

constant. The coefficient of volume expansion of the gas is

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

A copper rod of

88 c m

and an aluminum rod of unknown length have their increase in length independent of increase in temperature. The length of aluminum rod is

(α_{C u} = 1.7 \times 10^{- 5} K^{- 1} a n d α_{Al} = 2.2 \times 10^{- 5} K^{- 1})

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

A block of mass

10 kg

is kept on a rough inclined plane as shown in the figure. A force of

3 N

is applied on the block. The coefficient of static friction between the plane and the block is

0.6 .

What should be the minimum value of force

P,

such that the block does not move downward? (take

g = 10 m s^{- 2}

)

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

State the unit and dimensions of coefficient of convection?

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

It is hotter at the same distance over the top of a fire than it is on the side of it, mainly because :

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

Why convection cannot take place in a solid?

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

Explain why felt rather than air is used for thermal insulation even though the thermal conductivity of air is less than that of felt?

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

Ventilators are provided in rooms just below the roof. Why?

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

An ordinary electric fan does not cool the air; still, it gives comfort in summer. Explain.

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

Which method of heat transfer depends on gravity?

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

In which of the following process, convection does not takes place primarily?

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

A liquid of mass m and specific heat c is heated to a temperature 2T. Another liquid of mass

\frac{m}{2}

and specific heat 2c is heated to a temperature T. If these two liquids are mixed, the resulting temperature of the mixture is

EASY

Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

Permanent winds blowing toward the equator are called _____.

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

Assertion: It is hotter over the top of fire than at the same distance on the sides.

Reason: Air surrounding the fire conducts more heat upwards.

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

Trade wind is an example of which of these?

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Physics>Mechanics>Work, Energy and Power>Conservation of Mechanical Energy

The equatorial and polar regions of the earth receive unequal solar heat. The convection current arising due to this is called:

Which of the following is a result of mechanical weathering?

Important Questions on Work, Energy and Power

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