A particle moves along a straight line such that its displacement s at any time t is given by s = t³ − 6t² + 3t + 4 meter. Find speed in m/s, when acceleration is zero.
Physics · Mixed Chapter
JEE Mains

Question

A particle moves along a straight line such that its displacement s at any time t is given by s = t³ − 6t² + 3t + 4 meter. Find speed in m/s, when acceleration is zero.

G1 Physics · Accepted Answer

Step 1: s=t³−6t²+3t+4. Velocity v=ds/dt=3t²−12t+3. Step 2: Acceleration a=dv/dt=6t−12. Setting a=0 gives t=2 s. Step 3: v(2)=3×4−12×2+3=−9 m/s. Speed is its magnitude 9 m/s. Answer: 9.