NECO 2009 Physics · Question 4

The gravitational field intensity at a location X, in space, is two-fifths of its value on the earth’s…

Question

The gravitational field intensity at a location X, in space, is two-fifths of its value on the earth’s surface. If the weight of an object at X is 4.80N. what is its weight on the earth?

A.1.92N
B.2.88N
C.6.72N
D.8.00N
E.12.00N

Answer: E. 12.00N

Explanation written with AI and checked against the answer key

Analyze the question Weight is W = mg, where g is the gravitational field intensity. At X, g is two-fifths of its value on Earth's surface. We know the weight at X and need the weight on Earth. Concept For the same object (same mass), weight is directly proportional to g: W_X / W_E = g_X / g_E Solution Given g_X = (2/5) g_E and W_X = 4.80 N: W_X = (2/5) × W_E 4.80 = (2/5) × W_E W_E = 4.80 × (5/2) = 12.00 N Check: (2/5) of 12.00 = 4.80 ✓ The weight on Earth is larger, which makes sense because g is stronger on Earth than at X. This rules out options A and B, which are smaller than 4.80 N. Option D (8.00 N) would come from using 3/5 by mistake, and C does not come from the correct ratio. The correct answer is E. 12.00 N. Tip: When a question gives you a fraction of g, the weight scales by the same fraction. If the weight at X is a fraction of the weight on Earth, divide by that fraction (or multiply by its reciprocal) to get the Earth weight. Check that your answer is larger when the other location has weaker gravity.

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