Question

A ball of mass 0.2 kg is thrown vertically upwards by applying a force by hand. If the hand moves 0.2 m while applying the force and the ball goes upto 2 m height further, find the magnitude of the force. [consider g=10 m/s2]

Answer 1

The work/energy input to the system is

W=E=(F−mg)δ

This energy is completely transformed into potential energy so

(F−mg)δ=mgh

with

F=mg(1+h/δ)

here

δ=0.2[m]

m=0.2[K]

h=2[m]

then

F=0.2×10(1+20.2)=22[N]

Answer 2

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↠ A ball of mass 0.2 kg is thrown vertically

by applying a force by hand.

↠ hand moves 0.2 m while applying the

force and the ball goes 2 m heights

↠ g = 10 m/s²

$\huge\pink{\underline{\boxed{\mathbb{Given}}}}$]

↠ Mass of ball = 0.2 kg.

↠ Total height = 0.2 + 2 = 2.2 m

↠ Total displacement = 0.2 m

$\huge\pink{\underline{\boxed{\mathbb{To Find}}}}$]

The magnitude of the force.

SoLuTioN :--

↠ Work done = Difference in potential difference.

↠ FS = MGH.

↠ F = MGH / S

↠ F = 0.2 X 10 X 2.2 / 0.2

↠ F = 22 N