Question

Question #dcfec

Answer 1

`-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!

Answer 2

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...