Question

A body of mass 1 kg is projected vertically up with K.E equal to 196J. The height at which its K.E = P.E

Answer 1

since k.e=p.e
therefore,
196=mgh
here m=1kg
g=9.8m/s^2.
therefore
196=1*9.8*h
h=196/9.8
h=20m

Answer 2

Answer:

h1 = 10 m

Explanation:

let consider the point at which "kinetic energy = potential energy" as 'B' and ground as 'A' AND WE WILL TAKE GROUND AS REFERENCE

according to the law of conservation of mechanical energy

kinetic energy at A + potential energy at A = kinetic energy at B + potential energy at B

→ Here K.E at A = 196 J, P.E at A = 0 J AND K.E at B = x = P.E at B

⇒ K.E at B + P.E at B = K.E at A + P.E at A

⇒ x + x = 196 J + 0

⇒ 2x = 196 J

⇒ x = 196/2 ⇔ 98 [x= P.E at B = mgh1]

⇒ mgh1 = 98

⇒ 1×9.8×h1 = 98

⇒h1 × 9.8 = 98

∴ h1 = 98/9.8 = 10 m