Haizal O.

# Physics Work and Energy Question. Please check my answer.

A 5g apple is thrown straight upward with an initial velocity of 20 m/s @ a point of 1.5m height from ground.
Ignoring air friction, find:

a. Total mechanical energy of the apple at initial position.
b. Total potential energy of the apple at maximum position.

a) 5g = 0.005kg

Kinetic Energy = (1/2)(m)(v)^2
= (1/2)(0.005)(20)^2
= 1J

b) Finding max position,
s = (u^2 - v^2)/(2a)
= (20^2)/(2(9.81))
= 20.39m

Potential Energy = mgΔh
= (0.005)(9.81)(20.39-1.5)
= 0.9J

Is this correct? It feels wrong. Thank you in advance,

## 2 Answers By Expert Tutors

By:

Bob A. answered • 08/06/14

Tutor
4.9 (127)

20 Years Making Science and Maths Understandable and Interesting!

Haizal O.

Thank you Sir Stephen! Short and simple. Also thanks for the equation on my earlier question as well. (:
Report

08/06/14

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