Rankers Physics

Work Done by Constant and Variable Forces: Practice Problem & Solution

A force of (5 + 3x) N, acting on a body of mass 20 kg along the x-axis, displaces it from x = 2 m to x = 6 m. The work done by the force is
20 J
48 J
68 J
86 J

Solution Explained:

To solve this problem, we apply the core principles of Work Done by Constant and Variable Forces. Understanding the underlying formula is key to arriving at the correct answer below:

Work Done by Variable force is ∫F.dx, So

W= ∫(5 + 3x).dx= 5x+3x²/2

Using Limits from x=2 to x=6 we get

W= 68 J

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