Anyone can help me with this physics problem?
The acceleration of a particle is defined by the relation a = -k√v, where k is constant.
x = 0 and v = 81 m/s at t = 0
and v = 36 m/s x = 18 m
(a) the velocity of the particle when x = 24 m
(b) the time required for the particle to come to rest.