Question

Masses of two bodies are 1 kg and 4 kg respectively. If their kinetic energies are in 2:1 proportion, ratio of their speeds is (A) 2√2:1 (B) 1:√2 (c) 1:2 (D) 2:1

GSEB - Class 9 Chapter - 1. Work, Energy and Power Page 9

Answer 1

We know that kinetic energy is half of product of mass and velocity of a body.

So, KE =1/2 mv²

We have values

m1= 1 kg and m2 = 4 kg And v1:v2 =2:1

So, K1/ K2 = (m1/m2)(v1/v2)²

=> 2/1 =(1/4)(v1/v2)²

=> (v1/v2)² = 8/1

=> v1/v2 = 2√2/1

So, the answer is option A.

Answer 2

Answer:

option A

Explanation:

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