Newton’s second law application — find the force needed What constant force must be applied to a body of mass 100 kg to produce an acceleration of 5 m/s^2?
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A20 N
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B100 N
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C500 N
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DNone of these
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E50 N
Answer
Correct Answer: 500 N
Explanation
Introduction / Context:This is a direct application of Newton’s second law of motion, which relates force, mass, and acceleration. It is a staple calculation in engineering mechanics and physics.
Given Data / Assumptions:
- Mass m = 100 kg.
- Desired acceleration a = 5 m/s^2.
- Motion in a straight line; neglect friction and other resistances.
Concept / Approach:Newton’s second law states that the net force F required to produce an acceleration a on a mass m is F = m * a. This relationship is linear: doubling the mass or the acceleration doubles the required force.
Step-by-Step Solution:
Write the governing equation: F = m * a.Substitute m = 100 kg and a = 5 m/s^2.Compute: F = 100 * 5 = 500 N.Therefore, the required constant force is 500 N.Verification / Alternative check:If the same 500 N acted on a 50 kg body, the acceleration would be 10 m/s^2, consistent with the linear relationship. Scaling checks help confirm arithmetic.
Why Other Options Are Wrong:
- 20 N, 50 N, 100 N: Too small to generate the specified acceleration for a 100 kg mass.
- None of these: Incorrect because 500 N is available as an option and is correct.
Common Pitfalls:Confusing weight with mass (weight = m * g). Here we are asked for net force to create a given acceleration, not the weight of the object.
Final Answer:500 N