Question Part Points Submissions Used 1 2 0 /1 0 /1 1/5 1/5 Total 0 /2 A 1.50 ?

Question

Question Part Points Submissions Used 1 2 0/1 0/1 1/5 1/5 Total 0/2 A 1.50 ? 103-kg car starts from rest and accelerates uniformly to 19.3 m/s in 11.7 s. Assume that air resistance remains constant at 400 N during this time. (a) Find the average power developed by the engine W

(b) Find the instantaneous power output of the engine at t = 11.7 s, just before the car stops accelerating.
Question Part Points Submissions Used 1 2 0/1 0/1 1/5 1/5 Total 0/2 Question Part Points Submissions Used 1 2 0/1 0/1 1/5 1/5 Total 0/2 Question Part Points Submissions Used 1 2 0/1 0/1 1/5 1/5 Total 0/2 Question Part Points Submissions Used 1 2 0/1 0/1 1/5 1/5 Total 0/2 Question Part Points Submissions Used 1 2 0/1 0/1 1/5 1/5 1 2 0/1 0/1 1/5 1/5 Total 0/2 A 1.50 ? 103-kg car starts from rest and accelerates uniformly to 19.3 m/s in 11.7 s. Assume that air resistance remains constant at 400 N during this time. (a) Find the average power developed by the engine W

(b) Find the instantaneous power output of the engine at t = 11.7 s, just before the car stops accelerating.
A 1.50 ? 103-kg car starts from rest and accelerates uniformly to 19.3 m/s in 11.7 s. Assume that air resistance remains constant at 400 N during this time. (a) Find the average power developed by the engine W

(b) Find the instantaneous power output of the engine at t = 11.7 s, just before the car stops accelerating.
(a) Find the average power developed by the engine W

(b) Find the instantaneous power output of the engine at t = 11.7 s, just before the car stops accelerating.
Question Part Points Submissions Used

Explanation / Answer

a)

Fres=400 N

Power

P=Work/time=W/t=(F-Fres)*v

F=ma

W=m*a*d

m=1.50 ? 103 kg

avg power of car during the 11.7 s = F * Vavg

average velocity

Vavg=d/t

v^2-V0^2=2*a*d

v0=0

a*d=v^2/2=19.3^2/2=186.245

acceleration a=(v-v0)/t=19.3/11.7=1.65 m/s^2

d=186.245/1.65=112.9 m

Vavg=112.9/11.7=9.65 m/s

the average power

Pavg=(F-Fres)*Vavg=((1.50 * 103)*1.65-400)*9.65 =20023.75 Watts

b)

Instantaneous power at t = 11.7 P = (F-Fres) *v = ((1.50 * 103)*1.65-400)*19.3=40047.5 Watts

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