Question

The distance travelled by a particle is related to time $t$ as $x=4 t^2$ The velocity of the particle at $t-5 s$ is:-

• A. $8 \,m s^{-1}$
• B. $20\, ms ^{-1}$
• C. $25\, ms ^{-1}$
• D. $40\, ms ^{-1}$

Answer 1

Answer: (D)

$40\, ms ^{-1}$

Answer 2

The correct answer is (D) : $40\, ms ^{-1}$
x=4t2
v=dtdx​=8t
At t=5sec
v=8×5=40m/s