Editor Staff asked 1 year ago
A variable mass body with an initial mass of 10 kg is moving with a velocity of 7 m/s initially, after some time the velocity increases to 14 m/s, what is the new mass if the body is moving in the absence of any external force?
(a) 2.5 Kg
(b) 5 Kg
(c) 7.5 Kg
(d) 10 Kg
I had been asked this question in an interview.
Asked question is from Laws of Motion topic in portion Laws of Motion of Physics – Class 11
Select the correct answer from above options
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Editor Staff answered 1 year ago
Correct option is (b) 5 Kg
The best explanation: The body is moving in the absence of any external force thus the momentum remains conserved. m1v1 = m2v2. v1 = 7 m/s, m1 = 10 Kg, v2 = 14 m/s. On solving, we get, m2 = 5 kg. Hence, the correct answer is 5 Kg.
