A body of mass 2 textkg is thrown up vertically with kinetic energy of 490 textJ . If g=9.8 m s- 2 , the height at which the kinetic energy of the body becomes half of the original value, is

Question

A body of mass 2 textkg is thrown up vertically with kinetic energy of 490 textJ . If g=9.8 m s- 2 , the height at which the kinetic energy of the body becomes half of the original value, is (A) 50 m (B) 25 m (C) 12.5 m (D) 19.6 m

Tardigrade Admin · Accepted Answer

Initial kinetic energy is 490 textJ Let h be the height at which kinetic energy becomes half of the initial value (K E/2) = (490/2) = 245 textJ Gain in Potential energy at height h is mgh This is equal change in kinetic energy Δ K E = 490 textJ - 245 textJ = 245 textJ m g h = 245 textJ h = (245/2 × 9.8) = 12.5 textm

Q. A body of mass $2 kg$ is thrown up vertically with kinetic energy of $490 J$ . If $g = 9.8 m s^{- 2}$ , the height at which the kinetic energy of the body becomes half of the original value, is

$50 m$

$25 m$

$12.5 m$

$19.6 m$

Q. A body of mass 2kg is thrown up vertically with kinetic energy of 490J . If g=9.8ms−2 , the height at which the kinetic energy of the body becomes half of the original value, is

50m

25m

12.5m

19.6m

Initial kinetic energy is 490J Let h be the height at which kinetic energy becomes half of the initial value 2KE​=2490​=245J Gain in Potential energy at height h is mgh This is equal change in kinetic energy ΔKE=490J−245J=245J mgh=245J h=2×9.8245​=12.5m

Q. A body of mass $2 kg$ is thrown up vertically with kinetic energy of $490 J$ . If $g = 9.8 m s^{- 2}$ , the height at which the kinetic energy of the body becomes half of the original value, is

$50 m$

$25 m$

$12.5 m$

$19.6 m$