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An infinite number of masses, each of one kg, are placed on the x-axis at 1m, 2m, 4m from the origin. Find the magnitude of the gravitational field at the origin due to this distribution of masses.

a. 2G/√​7​N/kg
b. G/√​7N/kg
c. 4G/√​7N/kg
d. 8G/√​7N/kg

User Davinder
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1 Answer

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Final answer:

The gravitational field at the origin due to an infinite distribution of 1 kg masses placed at distances of 1m, 2m, 4m, etc., is found by summing the individual contributions of each mass. This involves a geometric series with a ratio of 1/4.

Step-by-step explanation:

The question asks for the magnitude of the gravitational field at the origin due to an infinite distribution of 1 kg masses placed at distances of 1m, 2m, 4m, etc., along the x-axis. To find this, we use the equation for the gravitational field g caused by a mass M, which is given by g = GM/d2, where G is the gravitational constant and d is the distance to the mass.

For each mass, the contribution to the gravitational field at the origin is g = G(1 kg)/d2. Summing over all masses, we have an infinite series: g = G(1 kg)/12 + G(1 kg)/22 + G(1 kg)/42 + .... This is a geometric series with a common ratio r = 1/4, and the sum of an infinite geometric series is a/(1 - r), where a is the first term of the series. Therefore, the gravitational field at the origin is g = G/(1 - 1/4), simplifying to g = (4/3)G. The correct answer must account for the specific distances given, so we would calculate the sums for 1m, 2m, 4m, etc., considering that these follow a geometric progression with ratio 1/4. The gravitational field strength at the origin due to these masses can then be calculated by summing their individual contributions.

User Twoam
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