physics
posted by E .
A certain car can accelerate from rest to the speed v in time T seconds.
(a) If the power output of the car remains constant, how long does it take for the car to accelerate from v to 3v, in terms of T?
(b) How fast is the car moving 9T after starting, in terms of v?

physics 
Elena
v=a•t
a=v/t
If the power output of the car remains constant,a=const
v(f) =v(i) +a•t1=>
3•v=v+v•t1/t
2•v=v•t1/t
t1=2t
(b) v2=a•9•t= v•9•t/t=9•v
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