Question

A Tesla Model S (with a mass of 2.2 x 103 kg) can accelerate from rest to

60 mph (27 m/s) on a horizontal track in 2.4 seconds.

a.Calculate the KEf


b.Calculate its power in Watts and in horsepower (1.0 hp = 745 W)

Answer 1

See the answers below.

Step-by-step explanation:

a) KEf, This term refers to the final kinetic energy i.e. when the velocity has reached 27 [m/s].

To calculate this energy we must use the following equation that relates velocity and mass to kinetic energy.

`E_(kin)=(1)/(2) * m*v^(2)`

where:

m = mass = 2.2*10³[kg]

v = velocity = 27 [m/s]

`E_(kin)=(1)/(2) *2.2*10^(3)*(27)^(2)\\E_(kin)=801900[J]`

b)

Power is defined as the amount of energy or work done over a certain time, it can be calculated by means of the following equation.

`P=E_(kin)/t`

where:

t = time = 2.4 [s]

P = Power [W]

Now replacing:

`P=801900/2.4\\P=334125[W]\\Now in Hp\\334125[w]*(1hp)/(745w) \\= 448.5[hp]`