Question

An object of mass 10 kg is moving with velocity of 10 ms−1. A force of 50 N acted upon it for 2 s. Percentage increase in its K.E is-

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Answer 1

Answer:

300 %

Explanation:

Given:

Mass (m) = 10 kg

Initial velocity (u) = 10 m/s

Force (F) = 50 N

Time (t) = 5 seconds

Initial Kinetic Energy:  

1 /2 mv²

⇒ 1/2 * 10 * 10 * 10

⇒ 500 J (Joules)

Final Velocity:

F = ma

⇒ 50 = 10 * a

⇒ a = 50/10 = 5 m/s²

v = u + at

⇒ v = 10 + (5 * 2)

⇒ v = 10 + 10 = 20 m/s

Final Kinetic Energy:

1/2 mv²

⇒ 1/2 * 10 * 20 * 20

⇒ 2000 J

Percentage Increase in the Kinetic Energy:

(Change In K.E/ Initial K.E) * 100

⇒ (2000-500)/500 * 100

⇒ 1500/500 * 100

= 300 %

Hence, the Kinetic Energy of the object increased by 300 %.

Answer 2

hope this will help u