Question

PLEASE ANSWER THIS QUESTION FAST!! Question - What is the work to be done to increase the velocity of a car from 20km/h to 40km/h if the mass of the car is 2000 kg?

Answer 1

Mass of the car (m) = 2000 kg

Initial velocity of the car (u) = 20 km/h

➠ u = 20 × ⁵/₁₈ m/s

➠ u = 5.56 m/s

Final velocity of the car (v) = 40 km/h

➠ v = 40 × ⁵/₁₈ m/s

➠ v = 11.12 m/s

★ Work - Energy theorem :

                  It states that , work done on a body is equals to the change in kinetic energy .

$:\implies \sf W=\Delta K$

$:\implies \sf W=K_f -K_i$

$: \implies \sf W=\dfrac{1}{2}mv^2-\dfrac{1}{2}mu^2$

$: \implies \sf W=\dfrac{1}{2}m(v^2-u^2)$

$:\implies \sf W=\dfrac{1}{2}(2000) \big[(11.12)^2-(5.56)^2 \big]$

$:\implies \sf \pink{W=92740.8\ J}\ \; \bigstar$

Work to be done is 92,740.8 J .

Answer 2

Answer:

Given :-

• A velocity of car from 20 km/h to 40 km/h if the mass of the car is 2000 kg.

To Find :-

• What is the work done.

Formula Used :-

$\boxed{\bold{\large{Work\: done\: =\: \dfrac{1}{2}m({v}^{2} - {u}^{2})}}}$

where,

• m = Mass
• v = Final velocity
• u = Initial velocity

Solution :-

Given :

● Mass (m) = 2000 kg

● Initial velocity (u) = $\sf 20\: km/h =\: 20 \times \dfrac{5}{18}$ = 5.56 m/s

● Final velocity (v) = $\sf 40\: km/h =\: 40 \times \dfrac{5}{18}$ = 11.12 m/s

According to the question by using the formula we get,

⇒ $\sf Work\: done\: =\: \dfrac{1}{\cancel{2}} \times {\cancel{2000}} \times \bigg[{(11.12)}^{2} - {(5.56)}^{2}\bigg]$

⇒ $\sf Work\: done\: =\: 1000 \times 92.7408$

➠ $\sf\bold{\red{Work\: done\: =\: 92740.8\: J}}$

$\therefore$ The work to be done is 92740.8 J .