Practicing Success
Starting from rest a particle moves in a straight line with acceleration $a = \{2 + |t – 2|\} m/s^2$. Velocity of particle at the end of 4 s will be |
16 m/s 20 m/s 8 m/s 12 m/s |
12 m/s |
The correct answer is Option (4) → 12 m/s Acceleration can be written as $a = 2 + 2 – t$ or $a = 4 – t$ for $t ≤ 2s$ and $a = 2 + t – 2$ or $a = t$ for $t ≥ 2 s$ Therefore, acceleration time graph of the particle will be as shown below Now since, $dv = a dt$ $v_f − v_i$ = area under (a-t) graph or $v_f −0=(4 × 4)-\frac{1}{2}(4)(2)$ $=12 m/s$ or velocity of particle at the end of 4s is 12 m/s. |