Question

What work is said to be done to increase the velocity of a car from

15 km/h to 30 km/h, if the mass of the car is 1000 kg? (Phy)​

Answer 1

Answer:

Explanation:

Given,

Initial velocity of the car, u = 15 km/h

Final velocity of the car, v = 30 km/h

Mass of the car, m = 1000 kg

To Find,

Work done

Formula to be used,

W = K.E

We know that

K.E = 1/2 × m × (v² - u²)

Solution,

Putting all the values, we get

W = 1/2 × m × (v² - u²)

⇒ W = 1/2 × 1000 × [(30)² - (15)²]

⇒ W = 500 × (900 - 225)

⇒ W = 500 × 675

⇒ W = 337500 J

Hence, the work done 337500 J.

Answer 2

Answer:

⠀⠀⠀⌬ Initial Velocity (u) = 15 km/h

⠀⠀⠀⌬ Final Velocity (v) = 30 km/h

⠀⠀⠀⌬ Mass of the car (m) = 1000 kg

⠀⠀⠀⌬ Work Done = ?

• According to the Question :

⇒ Work = ∆KE

⇒ Work = K.E.(After) - K.E.(Before)

⇒ Work = ½mv² - ½mu²

⇒ Work = ½m(v² - u²)

⇒ Work = ½ × 1000 × [(30)² - (15)²]

⇒ Work = 500 × [(30 + 15)(30 - 15)]

⇒ Work = 500 × 45 × 15

⇒ Work = 337500 Joules

∴ The Work done is 337500 Joules.