Question

The work required to increase the velocity of a particle from 18km/h to 72km/h, if mass

of particle is 2kg, is

A) 15J B) 225J C) 275 J D) 375 J​

Answer 1

Option (D) 375 J

Given,

• Initial velocity (u) = 18 km/h
• Final velocity (v) = 72 km/h
• Mass (m) = 2 kg

To Find,

• The work required to increase the velocity of a particle.

According to question,

[ First convert km/h ]

Initial velocity (u) = 18 km/h

⇒ 18 × 5/18

⇒ 5 × 1

⇒ 5 m/s

Final velocity (v) = 72 km/h

⇒ 72 × 5/18

⇒ 5 × 4

⇒ 20 m/s

According to the Work = Energy theorem,

⇒ Work done = Change in kinetic energy

⇒ W = ΔK.E

⇒ W = ¹/2 × m (v² - u²)

[ Put the values ]

⇒ W = ¹/2 × 2 (20² - 5²)

⇒ W = 1(400 - 25)

⇒ W = 1(375)

⇒ W = 375 J

Therefore,

The work required to increase the velocity of a particle is 375 J.

Answer 2

Answer:

D 375

Explanation:

it is a correct solution of the question