Question

An automobile has a mass of 1200 kg. What is its kinetic energy, in ki, relative to the road when traveling at a velocity of 50 km/h? If the vehicle accelerates to 100 km/h in 15 seconds, what is the change in power required?

Answer 1

Answer:

a)Ek=115759.26J

b)23.15kW

Explanation:

kinetic energy(Ek) is understood as that energy that has a body with mass when it travels with a certain speed, it is calculated by the following equation

$Ek=0.5mv^{2}$

for the first part

m=1200Kg

V=50km/h=13.89m/s

solving for Ek

$Ek=0.5(1200)(13.89)^2$

Ek=115759.26J

For the second part of the problem we calculate the kinetic energy, using the same formula, then in order to find the energy change we find the difference between the two, finally divide over time (15s) to find the power.

m=1200kg

V=100km/h=27.78m/s

$Ek=0.5(1200)(27.78)^2=462963J$

taking into account all of the above the following equation is inferred

ΔE=$\frac{Ek2-EK1}{T}=\frac{462963-115759.26}{15}  =23146.916W=23.15kW$