KinematicsMotion in a Straight Line (NEET (NTA)National Eligibility cum Entrance Test (Medical) Physics): Questions 35  39 of 47
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Question number: 35
» Kinematics » Motion in a Straight Line
Question
The motion of a body is given by the equation dv (t) /dt = 6.0  3v (t), where v (t) is speed in m/s and t in sec.
If body was at rest at t = 0
Choices
Choice (4)  Response  

a.  The speed varies with the time as v (t) = 2 (1 – e ^{5t}) m/s 

b.  The magnitude of the initial acceleration is 6.0 m/s2 

c.  The speed is 0.1 m/s when the acceleration is half the initial value 

d.  The terminal speed is 4 m/s 

Question number: 36
» Kinematics » Motion in a Straight Line
Question
A particle moves towards east with velocity 5 m/s. After 10 seconds its direction changes towards north with same velocity. The average acceleration of the particle is
Choices
Choice (4)  Response  

a.  m/s ^{2} SW 

b.  m/s ^{2} NW 

c.  zero 

d.  m/s ^{2} NE 

Question number: 37
» Kinematics » Motion in a Straight Line
Question
A 120 m long train is moving towards west with a speed of 10 m/s. A bird flying towards east with a speed of 5 m/s crosses the train. The time taken by the bird to cross the train will be
Choices
Choice (4)  Response  

a.  8 sec 

b.  14 sec 

c.  16 sec 

d.  12 sec 

Question number: 38
» Kinematics » Motion in a Straight Line
Question
P, Q and R are three coplanar forces acting at a point and are in equilibrium. Given P = 1.9318 kg wt, sin Q = 0.9659, the value of R is (in kg wt)
Choices
Choice (4)  Response  

a.  2 

b.  1 

c.  0.9659 

d.  0.5 

Question number: 39
» Kinematics » Motion in a Straight Line
Question
A man can swim with velocity v relative to water. He has to cross a river of width d flowing with a velocity u (w > v). The distance through which he is carried downstream by the river is x. Which of the following statements is correct?
Choices
Choice (4)  Response  

a.  If he crosses the river in minimum time x = du/v 

b.  x cannot be less than du/v 

c.  Force to be minimum he has to swim in a direction making an angle of π/2 sin 1 (v/u) with the direction of the flow of water. 

d.  x will be maximum if he swims in a direction making an angle of π/2 + sin1  1 (v/u) with direction of the flow of water. 
