Kinematics-Average Speed and Instantaneous Velocity (NEET (NTA)-National Eligibility cum Entrance Test (Medical) Physics): Questions 13 - 17 of 108

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Passage

When an airplane flies, its total velocity with respect to the ground is v total = v plane + v wind’ where v plane denotes the plane’s velocity through motionless air,

And v wind denotes the wind’s velocity. Crucially, all the quantities in this equation are vectors. The magnitude of a velocity vector is often called the “speed. ”

Consider an airplane whose speed through motionless air is 100 meters per second (m/s). To reach its destination, the plane must fly east.

The “heading” of a plane is in the direction in which the nose of the plane points. So, it is the direction in which the engines propel the plane.

Question number: 13 (3 of 3 Based on Passage) Show Passage

» Kinematics » Average Speed and Instantaneous Velocity

MCQ▾

Question

If the plane has an eastward heading, and a 20 m/s wind blows towards the southwest, then the plane’s speed is -

Choices

Choice (4) Response

a.

more than 100 m/s

b.

more than 80 m/s but less than 100 m/s

c.

80 m/s

d.

100 m/s

Question number: 14

» Kinematics » Average Speed and Instantaneous Velocity

MCQ▾

Question

The length of second’s hand in watch is 1 cm. The change in velocity of its tip in 15 seconds is

Choices

Choice (4) Response

a.

zero

b.

cm/sec

c.

cm/sec

d.

cm/sec

Question number: 15

» Kinematics » Average Speed and Instantaneous Velocity

MCQ▾

Question

A person aiming to reach the exactly opposite point on the bank of a stream is swimming with a speed of 0.5 m/s at an angle of 120° with the direction of flow of water. The speed of water in the stream is

Choices

Choice (4) Response

a.

lm/s

b.

0.433 m/s

c.

0.25 m/s

d.

0.5 m/s

Question number: 16

» Kinematics » Average Speed and Instantaneous Velocity

MCQ▾

Question

A ball is fixed to the end of a string and is rotated in a horizontal circle of radius 10 m with a speed of 20 m/sec. The acceleration of the ball will be -

Choices

Choice (4) Response

a.

30 m/s 2

b.

10 m/s 2

c.

20 m/s 2

d.

40 m/s 2

Question number: 17

» Kinematics » Average Speed and Instantaneous Velocity

Assertion-Reason▾

Assertion (Ꭺ)

Two projectiles are launched from the top of a cliff with same initial speed with different angles of projection. They reach the ground with the same speed

Reason (Ꭱ)

The work done by gravity is same in both the cases.

Choices

Choice (4) Response

a.

Both Ꭺ and Ꭱ are false

b.

Both Ꭺ and Ꭱ are true but Ꭱ is NOT the correct explanation of Ꭺ

c.

Both Ꭺ and Ꭱ are true and Ꭱ is the correct explanation of Ꭺ

d.

Ꭺ is true but Ꭱ is false

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