KinematicsAverage 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
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
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
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
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 (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 
