A particle travels in a straight line so that, t sec
after passing thru a fixed pt A, its velocity, v
m/s is given by v = 2 + 4 sin 2t. The particle first
instantaneously comes to rest at pt B.
Find the time when the particle reaches B.
(I set v = 0 and solve for t, what did I do wrong?)
Thanks. jt (Ans: 0.785 s)
v = velocity = (displacement / time) =/= speed
The particle travels in a straight line, but what they never
told you is that it is travelling to-and-fro on that line.
The time when the particle first comes to instantaneous rest, is
the time when the particle turns around in a U-turn ( Not
literally, just to give you an idea ), which will also be the time
when the particle first reaches maximum velocity.
Maximum v possible = 6, as maximum positive value of 4sin2t =
4.
Thus,
4sin2t = 4
sin2t = 1
t = 0.785 s