Question #dcfec

2 Answers
SCooke ยท Sunayan S
Oct 2, 2017

-0.85m It is underground!

Explanation:

At the "initial" location, the object's energy is all "potential". The rate of fall is not a part of the question - only the distance from the start (-2m).
PE_"grav" = m xx g xx h

where
m = mass (kg)
g = 9.8 N/kg
h = height (m)
900 = 80 xx 9.8 xx h ; h = 900/(80 xx 9.8) = 1.15m

1.15 - 2 = -0.85m It is underground!

Sunayan S
Oct 2, 2017

See the answer below...

Explanation:

Suppose,it is at the initial height color(red)h meter.

Hence at the toppest point it has potential energy of 80xxgxx(h+2)joule

As any point of a body moving in a vertical way has a constant mechanical energy so we can write that:-
80xxgxx(h+2)=900
=>80xx10xx(h+2)=900
=>h+2=1.125

Here something wrong...
Need the question to be double checked...as color(red)h becomes -ve
Though height might be negative but in this case...

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