Question

what is the work done to be done to increase the velocity of a car from 18 km/hr to 90 km/hr,if the mass of car is 2000 kg ?

Answer 1

Answer:

hope it will help you:-)

Answer 2

Answer:

If the mass of the car is 2000 kg, the work done to be done to increase the velocity of a car from 18 km/hr to 90 km/hr will be $600000\ J$

Explanation:

According to the work-energy theorem,

Work done (W) = Change in kinetic energy (Δ K.E)

Let m be the mass and v is the velocity of the object. Then the expression for kinetic energy is given by,

Kinetic energy (K.E) = $\frac{1}{2} m V^{2}$      ...(1)

Change in K.E = $\frac{1}{2}m\ \Delta V$

Where $\Delta V = v-u$

So,

$W = \frac{1}{2}m\times (v^{2} -u^2)$                  ...(2)

In the question, it is given that,

$m = 2000\ kg$

$v= 18\ km/h = 18\times \frac{5}{18} = 5\ m/s$

$v= 90\ km/h = 90\times \frac{5}{18} = 25\ m/s$

Substitute the values into equation (2),

$W = \frac{1}{2}\times 2000\times (25^2-5^2) =600000 \ J$

Thus the work done =  $600000\ J$