Question

A force F = 20 + 10y action a particle in y-direction where F is in newton and y in meter. Work done by this force to move the particle from y = 0 to y = 1 m is :

• A. 25J
• B. 20J
• C. 30J
• D. 5J

Answer 1

Answer: (A)

25J

Answer 2

Work done by variable force is
$W =\int^{y_{f}}_{y_i} Fdy$
Here, $y_{i} =0, y_{f} = 1m$
$\therefore W = \int^{1}_{0} \left(20+10y\right)dy$
$= \left[20y + \frac{10y^{2}}{2}\right]^{1}_{0} = 25J$