Question

Displacement of an object of mass 2kg varies as s = 3$t^2$ + 5. Find work done by man from t = 0 to t = 5 sec.

• A. 100 J
• B. 200 J
• C. 500 J
• D. 900 J

Answer 1

The correct option is D 900 J

$V=\frac{ds}{dt}=6t$

Initial kinetic energy $=\frac{1}{2}\times 2\times (0{)}^2$

Final kinetic energy $=\frac{1}{2}\times 2\times (30{)}^2$

$W=K_f-K_i=900$ J