It is easier to roll a barrel full of coal tar than to pull it because
A. the full weight of the barrel comes into play when it is pulled
B. the rolling friction is much less than the sliding friction
C. more surface area of the barrel is in contact with the road when it is pulled
D. coal tar is a liquid and it flows in the barrel when it is rolled
Answer: Option B
Solution(By Examveda Team)
When a body slides (moves with all its surface area in contact) over another body, the resistance faced is due to sliding friction. Hence rolling friction is less than the sliding friction. Thus it is easier to roll a barrel full of coal tar than to pull it.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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