Question

What is the work to be done in increase the velocity of a car from 30 km h-¹ to 60 km h-¹ if the mass of the car is 1500 kg?​

Answer 1

Answer:

156375 J.

Explanation:

Mass of the car , m = 1500 kg,

initial velocity of car , u = 30 km h-¹

30 × 1000 m

_____________

60 × 60 s

= 8.33 ms-¹.

Similarly , the final velocity of the car ,

v = 60 km h-¹

= 16.67 m s-¹

Therefore , the initial kinetic energy of the car ,

Eki = 1/2 mu²

= 1/2 ×1500 kg × (8.33 ms-¹)²

= 52041.68 J.

The final kinetic energy of the car ,

Ekf = 1/2 × 1500 kg × ( 16.67 m s-¹)²

= 208416.68 J.

Thus , the work done = Change in kinetic energy

= Ekf - Eki

156375 J.

Answer 2

Answer:

Explanation:

m=1500kg,

u=30kmh-¹

30×1000m

60×60s

=8.33ms-¹.

finalvelocityofthecar,

v=60kmh-¹

=16.67ms-¹

initialkineticenergyofthecar,

Eki =1/2mu²

=1/2×1500kg×(8.33ms-¹)²

=52041.68J.

=>>

Ekf =1/2×1500kg×(16.67ms-¹)²

=208416.68J.

Thus,theworkdone=Changeinkineticenergy

=Ekf -Eki

156375J.

Hope it will help you with