Question

A variable force F acts along the X-axis given by

F = (3x² – 2x + 1) N. The work done by the force when a particle of mass 100 g moves from x = 50 cm to x = 100 cm is–

• A. 0.625 N
• B. 6.25 N
• C. 0.0625 N
• D. 62.5

Answer 1

Answer: (A)

0.625 N

Answer 2

= $\int _ { 0.5 } ^ { 1 } \mathrm {~F} . \mathrm { dx }$ = $\int _ { 0.5 } ^ { 1 } \left( 3 x ^ { 2 } - 2 x + 1 \right) d x$

= (1 – 0.5³) – (1 – 0.5²) + (1 – 0.5)

= (1 – 0.125) – (1 – 0.25) + (0.5)

= 0.875 – 0.75 + 0.5

=0.625