Question

An object of mass 40 kg is raised to a height of 5 m above the ground. What is its potential energy? If the object is allowed to fall, find its kinetic energy when it is half-way down.

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Answer 1

it's potential energy = mgh

= 40× 5 × 10

= 2000 joule.

yes

.

v^2 - u2 = 2 as

v^2 = 2as. ( u = 0)

v^2 = 2× 10 × 5/2

v^2 = 50.

eK = 1/2 m v^2

= 1/2 × 40× 50

= 1000 joule

energy is constant

of if potential energy is 2000 then kinetic energy is 2000 j

according to the question so the kinetic energy must be 1000 at half diatance

Answer 2

Answer:

mass= 40kg

height = 5m

acceleration due to gravity = 10 m/s²

initial velocity = 0 m/s

potential energy = mgh

40×10×5= 2000joules

height when object is half way down =2.5 m

kinetic energy =½mv²

using third equation of motion

2gh=v²-u²

2× 10×2.5= v² - 0

50m/s = v²

kinetic energy = ½ ×40×50

= 1000 joules