Question

If a car of mass 900 kg accelerates from zero to 72 km/hr in 10 sec, find the power of the engine​

Answer 1

Answer:

Mass of the car m=1000 kg

Initial velocity of car v  

1

​  

=0

Final velocity of car v  

2

​  

=100km/h=100×  

18

5

​  

m/s=27.78m/s

Average power of car=change in kinetic energy per unit time=  

t

2

1

​  

mv  

2

​  

 

2

−  

2

1

​  

mv  

1

​  

 

2

 

​  

,since v  

1

​  

=0

So,average power of car=  

t

2

1

​  

mv  

2

​  

 

2

 

​  

 

                                =  

5

2

1

​  

×1000×27.78  

2

 

​  

 

                                =7.71×10  

4

W