Question

What work is said to be done to increase the velocity of a car from 35m/s to 70 km/h, if the mass of the car is 1800 kg?

urgent..!!

Answer 1

Answer:

The work done equals 3307500 J or 3.31 MJ.

Explanation:

Given information

• Mass of the car $m=1800 \text{ kg}$.
• Initial velocity $v_1=35 \text{ m/s}$.
• Final velocity $v_2=70 \text{ m/s}$.

According to work energy theorem, the work done is equals to the change in kinetic energy i.e.,

$W=K.E_f-K.E_i\\=\frac{1}{2}mv_2^2-\frac{1}{2}mv_1^2$

Substituting all known values,

$W=\frac{1}{2}\times(1800 \text{ kg})\times(70\text{ m/s})^2-\frac{1}{2}\times(1800 \text{ kg})\times(35\text{ m/s})^2\\=3307500 \text{ J}\\\approx3.31 \text { MJ}$

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