Editor Staff asked 1 year ago
A force of 600 N elongates a spring from its natural length of 18 cm to a length of 20 cm. What is the work done?
(a) 116J
(b) 114J
(c) 118J
(d) 120J
I have been asked this question during an interview for a job.
This key question is from Work Done by a Variable Force topic in division Work, Energy and Power of Physics – Class 11
Select the correct answer from above options
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Editor Staff answered 1 year ago
The correct choice is (b) 114J
The best explanation: The force on a spring stretched by x meters is given by F = k*x where k is the spring constant. So, 600 = k*(2/100). Now k = 3*10^4, and hence F = 30000*x. W =
∫
x2
x1
F * dx =
∫
0.2
0.18
30000 * x * dx = 114 J.
