A ball is thrown vertically upward from the ground. It crosses a point at the height of 25 m twice at an interval of 4 seconds. The ball was thrown with the velocity of
A. 18 m/s
B. 25 m/s
C. 30 m/s
D. 36 m/s
Answer: Option C
Solution (By Examveda Team)
The interval between object pass the same point is 4 sec.That means in 2 sec, object reaches the top and in next 2 sec, it again reaches the same point.
By the info given, we can find the velocity of that point by using : v=u+(-gt)
0= u - 10×2
u = 20
Then the velocity at 25m is 20m/sec.
so the initial velocity is
−v2 = u2 + (−2gh)
400 = u2 − 2x 10 x 25
u2 = 900
=> u = 30 m/s
Which of the following terms is not used in the field of physics?
A. Latent heat
B. Nuclear fusion
C. Refractive index
D. Stock value
Radiocarbon is produced in the atmosphere as a result of
A. Collision between fast neutrons and nitrogen nuclei present in the atmosphere.
B. Action of ultraviolet light from the sun on atmospheric oxygen.
C. Action of solar radiations particularly cosmic rays on carbon dioxide present in the atmosphere.
D. Lightning discharge in atmosphere.
It is easier to roll a stone up a sloping road than to lift it vertical upwards because
A. Work done in rolling is more than in lifting.
B. Work done in lifting the stone is equal to rolling it.
C. Work done in both is same but the rate of doing work is less in rolling.
D. Work done in rolling a stone is less than in lifting it.
The absorption of ink by blotting paper involves:
A. Viscosity of ink
B. Capillary action phenomenon
C. Diffusion of ink through the blotting
D. Siphon action

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