Rest and Motions Kinematics Obj-1 HC Verma Solutions Vol-1 Chapter-3

Rest and Motions Kinematics Obj-1 (MCQ-1) HC Verma Solutions Ch-3 Vol-1 Concept of Physics for Class-11. Step by Step Solution of Objective -1 (MCQ-1) Questions of Chapter-3 Rest and Motions Kinematics (Concept of Physics) .Visit official Website CISCE for detail information about ISC Board Class-11 Physics.

Rest and Motions Kinematics Obj-1 (MCQ-1) HC Verma Solutions Ch-3 Vol-1 Concept of Physics for Class-11

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Rest and Motions Kinematics Obj-1 (MCQ-1)

HC Verma Solutions of Ch-3  Vol-1 Concept of Physics for Class-11

(Page-49)

Question-1

Answer-1

The option (b) 70 km/h towards south-west. is correct

Explanation:

As velocity and acceleration are in opposite directions, velocity will become zero after some time (t) and the particle will return.

∴0 = u− a t
⇒  t=  u/a

Because the value of acceleration is not given, we cannot say that the particle will return after/before 10 seconds.

Question-4

A person travelling on a straight line moves with a uniform velocity v₁ for some time and with uniform velocity v₂ for the next equal time. The average velocity v is given by

Answer-4

The option (a) v = (v₁+ v₂) / 2  is correct

Explanation:

Question-5

A person travelling on a straight line moves with a uniform velocity v₁ for a distance x and with a uniform velocity v₂ for the next equal distance. The average velocity v is given by

Answer-5

The option (c)  is correct

Explanation:

Question-6

A stone is released from an elevator going up with an acceleration a. The acceleration of the stone after the release is

(a)  a upward

(b) (g − a) upward

(c) (g − a) downward

(d) g downward

Answer-6

The option (d)  g downward is correct

Explanation:

Gravity is the only force acting on the stone when it is released. And, we know that gravity is always in the downward direction

Question-7

A person standing near the edge of the top of a building throws two balls A and B. the ball A is thrown vertically upward and B is thrown vertically downward with the same speed. The ball A hits the ground with a speed v_A and the ball B this the ground with a speed v_B. We have

(a) v_A > v_B

(b)  v_A < v_B

(c) v_A = v_B

(d) the relation between v_A and v_B depends on height of the building above the ground.

Answer-7

The option (c) v_A = v_B is correct

Explanation:

Total energy of any particle =

Both the particles were at the same height and thrown with equal initial velocities, so their initial total energies are equal. By the law of conservation of energy, their final energies are equal.

At the ground, they are at the same height. So, their P.E. are also equal; this implies that their K.E. should also be equal. In other words, their final velocities are equal

Question-8

In a projectile motion the velocity

(a) is always perpendicular to the acceleration

(b)  is never perpendicular to the acceleration

(c) is perpendicular to the acceleration for one instant only

(d)  is perpendicular to the acceleration for two instants.

Answer-8

The option (c) is perpendicular to the acceleration for one instant only is correct

Explanation:

 In projectile motion, velocity is perpendicular to acceleration only at the highest point. Here, velocity is along the horizontal direction and acceleration is along the vertically downward direction.

Question-9

Two bullets are fired simultaneously, horizontally and with different speeds from the same place. Which bullet will hit he ground first?

(a) the faster one

(b) the slower one

(c) both will reach simultaneously

(d) depends on the masses.

Answer-9

The option (c) both will reach simultaneously is correct

Explanation:

Because the downward acceleration and the initial velocity in downward direction of the two bullets are the same, they will take the same time to hit the ground and for a half projectile.

Question-10

The range of a projectile fired at an angle of 15° is 50 m. If it is fired with the same speed at an angle of 45°, its range will be

(a) 25 m

(b)  37 m

(c) 50 m

(d) 100 m

Answer-10

The option (d) 100 m is correct

Explanation:

Question-11

Two projectiles A and B are projected with angle of projection 15° for the projectile A and 45° for the projectile B. If R_A and R_B be the horizontal range for the two projectiles, then

(a) R_A < R_B

(b)  R_A > R_B

(c)  R_A = R_B

(d) the information is insufficient to decide the relation of R_A with R_B.

Answer-11

The option (d) the information is insufficient to decide the relation of RA with RB. is correct

Explanation:

Horizontal range for the projectile,

Information of the initial velocity is not given in the question

Question-12

A river is flowing from west to east at a speed of 5 metres per minute. A man on the south bank of the river, capable of swimming at 10 metres per minute in still water, wants to swim across the river in the shortest time. He should swim in a direction.

(a) due north

(b) 30° east of north

(c)  30° north of west

(d)  60° east of north.

Answer-12

The option (a) due north is correct

Explanation:

If the man swims at any angle east to the north direction, although his relative speed will increase, he will have to travel a larger distance. So, he will take more time.

If the man swims at any angle west to the north direction, his relative speed will decrease. So, he will take more time

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Page-50

Question-13

In the arrangement shown in figure the ends P and Q of an inextensible string move downwards with uniform speed u. Pulleys A and B are fixed. The mass M moves upwards with a speed

(a) 2u cos θ

(b) u/cos θ

(c) 2u/cos θ

(d) u cos θ

Answer-13

The option (b) u/cos θ is correct

Explanation:

Along the string, the velocity of each object is the same.

—: End of Rest and Motions Kinematics Obj-1 (MCQ-1) HC Verma Solutions Ch-3 Vol-I :–

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