Question

A body of mass 4 kg is moving with momentum of 8 kg ms−1. A force of 0.2 N acts on it in the direction of motion of the body for 10 s. The increase in kinetic energy is​

Answer 1

___________________

★ Gɪᴠᴇɴ ★

• Mass of the body = 4kg
• Momentum of the body = 8 kg ms-¹
• Force = 0.2 N
• Time = 10 s

___________________

☯ Tᴏ Fɪɴᴅ ☯

• The increased K.E.

___________________

✪ Sᴏʟᴜᴛɪᴏɴ ✪

Momentum = mass × velocity

↠ P = mu

↠ u = P/m

↠ u = 8/4

↠ u = 2ms-¹

Acceleration = force/mass

↬ a = 0.2N/4kg

↬ a = 0.05ms-²

Distance travelled by the body in 10s

⇝ d = ut + ½ at²

⇝ d = (2)(10)+½(0.05)(10)²

⇝ d = 20+2.5

⇝ d = 22.5m

Work done

→ W = Fd

→ W = (0.2N)(22.5m)

→ W = 4.5 J

★ The increased K.E. is 4.5J

___________________