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Sheetal has taken an empty bottle and fixed a deflated balloon on its mouth. She placed the bottle in a container filled with hot water. After some time, the balloon gets inflated as shown. What could be the most appropriate reason for this?


A Air when gets heated becomes heavier and rises up.
B Air when gets heated becomes lighter and settles down.
C Air when gets heated becomes heavier and settles down.
D Air when gets heated becomes lighter and rises up.

Identify X, Y and Z from the given figure and select the correct statement regarding them.


AZ is attached to bones whereas X is not attached to bones
BY is voluntary muscle whereas Z is involuntary muscle.
CX is very strong muscle that works continuously.
DNone of these

A particle moves on a circular path of radius 7 m with uniform speed of 11 m/s. If it reaches point T from point S, a diametrically opposite point, then during this interval

(i) The average acceleration is zero.
(ii) The average velocity is zero.
(iii) The average acceleration is 11 m/s².
(iv) The average velocity is 7 m/s.
Which of the following options is correct?

A(i) and (ii) only
B(ii) and (iii) only
C(iii) and (iv) only
D(i) and (iv) only

A student plotted the following four graphs representing the variation of velocity v of sound in a gas with the pressure P for a given temperature. Which one is correct?

A
B
C
D

A cricket ball of mass 150 g moving with a speed of 126 km/h hits at the middle of the bat, held firmly at its position by the batsman. The ball moves straight back to the bowler after hitting the bat. Assume that the ball rebounds with same speed and they remain in contact for 0.001 s, the force that the batsman had to apply to hold the bat firmly at its place would be

A10.5 × 10^-4 N
B2.1 × 10³ N
C1.05 × 10⁴ N
D2.1 × 10⁴ N

A boy throws a cricket ball from the boundary to the wicket-keeper. If the frictional force due to air cannot be ignored, the forces acting on the ball at the position X are represented by


A
B
C
D

A body is dropped from a height h and touches the ground at a speed of 1.2√gh. The work done by air friction is

Amgh
B0.72 mgh
C0.28 mgh
D- 0.28 mgh

A truck accelerates from speed v to 2v. Work done during this is

AThree times as the work done in accelerating it from rest to v.
BSame as the work done in accelerating it from rest to v.
CFour times as the work done in accelerating it from rest to v.
DLess than the work done in accelerating it from rest to v.

Observe the given reaction sequence carefully.

Acetic acid + Sodium hydrogen carbonate (i)
(i) + Ca(OH)₂ (ii) + Water

What could (i) and (ii) be?

The first wheels were made from _____.

AWood
BStone
CMetal
DIron