Questions
21
As per the statement given in Q.9 above, What change it will take place for the potential energy of the car
Answer: It will remain the same
22
A car with mass ‘M’ is moving on horizontal road with velocity ‘v’. Driver applies accelerator and increases it speed 3 times to ‘3v’. The final K.E. acquired by the car will be :
Answer: 4.5 Mv2
23
An external force is being applied on an object at some angle and it causes the object either to be pulled or pushed on a rough surface. Which of the following holds true ?
Answer: It is easier to pull the object
25
A runner, while moving, is facing a wind from the opposite direction. The work done by the wind on runner will be
Answer: Negative
26
The commercial unit of energy consumption in households, industries and commercial establishments is
Answer: KW h (kilowatt hour)
28
A soldier makes a swing jump between two points, by holding one end of a rope, other end of which is tied to some higher point. Work done by rope in jumping of soldier from one point to another is an example of :
Answer: Zero work done
29
In winters, rubbing of hands together for some time, causes a sensation of warmth mainly because of
Answer: heat caused by the force of friction
30
A dog weighing 25 kg, while chasing a cat, jumps over a fence of height 1.6 m. What is the potential energy of dog at the top of fence ?
(Take gravity due to earth 'g'=10 m s-2 )
Answer: 380 Joules
31
Two objects A and B are moving with same momentum. Mass of object 'B' is greater then mass of object 'A'. Which of the two object will have higher kinetic energy?
Answer: Object A
33
Which of the following is NOT a property of particles of a matter?
Answer: The particles of matter are in stationery state.
36
Which of the following has minimum spaces among the particles?
Answer: Solids
37
During summer, water kept in an earthen pot becomes cool because of the phenomenon of
Answer: evaporation
39
A change of state directly from solid to gas without changing into liquid state (or vice versa) is called
Answer: Sublimation
