A body attached to a spring balance weighs 10 kg on the Earth. The body attached to the same spring balance is taken to a planet where gravity is half that of the Earth. The balance will read

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Q: 74 (NDA-I/2012)
A body attached to a spring balance weighs 10 kg on the Earth. The body attached to the same spring balance is taken to a planet where gravity is half that of the Earth. The balance will read

question_subject: 

Science

question_exam: 

NDA-I

stats: 

0,16,14,4,8,16,2

keywords: 

{'spring balance': [0, 0, 0, 2], 'same spring balance': [0, 0, 0, 1], 'balance': [0, 0, 1, 1], 'gravity': [0, 0, 0, 6], 'kg': [0, 1, 9, 24], 'planet': [4, 0, 1, 1], 'earth': [0, 1, 1, 1], 'body': [27, 3, 23, 37]}

When a body is attached to a spring balance, the reading on the balance indicates the weight of the body. Weight is the force exerted on an object due to gravity.

In this question, the body weighs 10 kg on Earth. This means that the force of gravity acting on the body on Earth is (mass x acceleration due to gravity) or (10 kg x 9.8 m/s^2) = 98 N.

Now, we take the same body attached to the spring balance to a planet where gravity is half that of Earth. This means that the acceleration due to gravity on this planet is (9.8 m/s^2 / 2) = 4.9 m/s^2.

The weight of the body on this planet can be calculated using the formula weight = mass x acceleration due to gravity. So, the weight of the body on this planet is (10 kg x 4.9 m/s^2) = 49 N.

Therefore, the reading on the spring balance will be 49 N, which can be converted to kilograms as (49 N / 9.8 m/s^2) = 5 kg.

Hence, option 3 (5 kg) is the correct answer