Question

A) What do you mean by work. Give two examples each of positive work done , negative work done and zero work done?
B) what is the work to be done to increase the velocity of a car from 18 km/h to 90 km/h. The mass of car is 2000 kg.​

Answer 1

Answer:

Initial velocity u=30 km/h=30×

18

5

=

3

25

m/s

Final velocity v=60 km/h=60×

18

5

=

3

50

m/s

Mass m=1500 kg

Work done W=

2

1

mv

2

−

2

1

mu

2

⟹ W=

2

m

(v

2

−u

2

)=

2

1500

×((

3

50

)

2

−(

3

25

)

2

)=156187 J