Physics Power?
A 1000 kg sports car accelerates from rest to 25.0 m/s in 7.50 s. What is the average power output of the automobile engine? Please show work. I do not know how to solve this.
A 1000 kg sports car accelerates from rest to 25.0 m/s in 7.50 s. What is the average power output of the automobile engine? Please show work. I do not know how to solve this.
billrussell42
Favorite Answer
a = Δv/Δt = 25/7.5 = 3.333 m/s²
d = ½at² = ½3.333•7.5² = 93.75 m
F = ma = 1000 x 3.333 = 3333 N
Work = Fd = 3333 N x 93.75 m = 312460 J
power = work/time = 312460 J/7.5 s = 41700 J/s or watts
or
a = V/t
d = ½at² = ½(v/t)t² = ½vt
F = ma = mv/t
W = Fd = (mv/t)(½vt) = ½mv²
P = W/t = ½mv²/t = ½1000•25²/7.5 = 41700 w
az_lender
The gain of kinetic energy is (1/2)(1000 kg)(25.0 m/s)^2
= 312.5 kJ.
As this was achieved in 7.5 seconds,
the average power was (312.5 kJ)/(7.5 s) = 41.7 kW.