Question

A body of mass 2 kg is thrown upward with an energy 490 J. The height at which its kinetic energy would become half of its initial kinetic energy will be [ $g = 9.8 \mathrm {~m} / \mathrm { s } ^ { 2 }$ ]

• A. 35 m
• B. 25 m
• C. 12.5 m
• D. 10 m

Answer 1

Answer: (C)

12.5 m

Answer 2

If the kinetic energy would become half, then Potential energy = $\frac { 1 } { 2 }$ (Initial kinetic energy)

⇒ $m g h = \frac { 1 } { 2 } [ 490 ]$ ⇒ $2 \times 9.8 \times h = \frac { 1 } { 2 } [ 490 ]$ ⇒ $h = 12.5 m$