Question

The position of a body changes as x = 3t², the velocity at t = 2 sec
a. 6m/s
b. 12m/s
c. 18 m/s
d. 24 m/s

Answer 1

Answer:

correct option is (b) 12 m/s

Explanation:

for explanation refer to the attachment

Answer 2

x = displacement = 3t²

$u = \frac{d}{dx} 3 {t}^{2} \\ \\ u = \frac{d}{dx} 3 \times 2 \times {t}^{1} \\ \\ u = 6t$

t = 2 s

u = 6(2)

u = 12 m/s

Option B) 12 m/s