A person lifts luggage of 20 kg from the ground and puts it on his head 2m above the ground. Calculate the work done by him. (g = 10 )
A. 20 J
B. 400J
C. 200J
D. 40J
Answer: Option B
Solution(By Examveda Team)
Total work done in lifting and moving the luggage is 588 Joules.Explanation :
1. work done in lifting the luggage
= potential energy of the luggage
= mgh
where,
m = mass = 20 kg
g = acceleration due to gravity = 9.8 m/s²
h = height = 3 m
Hence,
P = mgh = 20 x 9.8 x 3
= 588 J
2. work done in moving the object,
Since now weight of the luggage is acting in downward direction and the movement is in horizontal direction, hence work done in moving the luggage is zero because component of force along horizontal direction is zero.
Total work done = 588 + 0 = 588 J.
Hence total work done in lifting and moving the luggage 588 J.
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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