Question

what work is to be done in order to increase the velocity of a car from 18 km per hour to90km per hour.if the mass of the car is2000kg

Answer 1

$\red{HEY\:BUDDY!!}$

HERE'S THE ANSWER...

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♠️ According to work energy theorem change in kinetic energy is also know as work done , i.e.

=> $\blue{ Work\:= K_{f} - K_{i}}$

⏺️ Mass ( m ) = 2000 kg

⏺️ Initial velocity ( u ) = 18 Km/h

=> 18 × 5 / 18

=> 5 m/s

⏺️Final Velocity ( v ) = 90 Km/h

=> 90 × 5 / 18

=> 25 m/s

▶️ Now , putting values in formula

=> $\texttt{ W\:=\: K_{f} - K_{i}}$

=> $\texttt{ W\:=\: 1/2 m ( v^{2} - u^{2})}$

=> $\texttt{ W\:=\: 1/2 (2000) ( 25^{2} - 5^{2})}$

=>$\texttt{ W\:=\: (1000) (625 - 25)}$

=> $\texttt{ W\:=\: (1000) (600)}$

=>$\boxed{ W\:=\: 6 × 10^5 Joules}$


HOPE HELPED..

$\red{JAI \:HIND..}$

PEACE✌️☺️

Answer 2

we know

work = 1/2 mv^2 - 1/2 mu^2

= 1/2 m ( v^2 - u^2 )

= 1/2 × 2000 ( 25 × 25 - 5 × 5 )

= 1000 ( 625 - 25 )

= 1000 × 600

= 600000 Joules