Question

A particle is moving along x-axis. Its
position is varying with time as x = (t2-
12t - 1)m. What is the speed at t = 2
sec.:-
(A) 4 m/sec.
(B) 8 m/sec.
(C) 16 m/sec.
(D) 32 m/sec.​

Answer 1

Explanation:

x = t²-12t-1

t = 2

so, x => (2)²-12(2)-1

= 4-24-1

= 21 m

v = d/t = 21/2 = 10.5m/s

(or)

DX/dt = DV

DV = d/dt( t²-12t-1)

= 2t-12-0

= 2t - 12

= 2(2)-12

= -8 m/s(2 option )