A point mass of 0.5 kg moves along the x-axis according to x=t²+2t, where x is in metres and t is in seconds. Find the work done by all forces during the interval t=0 to t=2 s.
Physics · Work , Power and Energy · kinetic enegy and work engery theorem
JEE Mains

Question

A point mass of 0.5 kg moves along the x-axis according to x=t²+2t, where x is in metres and t is in seconds. Find the work done by all forces during the interval t=0 to t=2 s.

G1 Physics · Accepted Answer

x=t²+2t ⇒ v=dx/dt=2t+2. Thus v(0)=2 m/s and v(2)=6 m/s. By the work-energy theorem, W=ΔK=½m[v(2)²-v(0)²]=½(0.5)(36-4)=8 J.