Answer: The answers are given below;
a) 336093,12
b) 9602,66
c) 9602,66
Explanation:
First let's start making 89 km/h to m/s. To do this;
[tex]\frac{89 . 1000}{3600} = 24,72 m/s[/tex]
a ) Now let's find its kinetic energy; As we know kinetic energy formula is [tex]\frac{1}{2} mv^{2}[/tex]
Car's kinetic energy after 35 seconds is:
[tex]\frac{1}{2} .1100.24,72^{2} = 336093,12 kg\frac{m^{2} }{s^{2} }[/tex]
b ) Because the road is horizontal it is a fact that W(work) = Δ[tex]E_{k}[/tex]
Therefore the average power required is;
P(Power) = [tex]\frac{W(Work)}{t(time)}[/tex] and;
[tex]P_{avg} = \frac{336093,12}{35} = 9602,66[W/s][/tex]
c ) Instantaneous power can be calculated as:
[tex]P_{ins}=F.V[/tex]
Now, since we assume that acceleration is constant, we can use the formula x = V.t to find x(distance). Then we can find F as we know W=F.x
[tex]x = 24,72.35=865,2[/tex] and
[tex]W=336093,12 = F.865,2[/tex] → [tex]F = 388,457[/tex]
therefore the instantaneous power at the end of 35 seconds is:
[tex]P = 388,457. 24,72 = 9602,66[W/s][/tex]
