A2.80 kg mass is dropped from a height of 4.50 m. find its kinetic energy(ke) at the moment it is dropped

Zero

Explanation:

The kinetic energy of an object is given by

where

m is the mass of the object

v is its speed

In this problem, the mass of the object is

m = 2.80 kg

while its speed when it is dropped is zero, so

v = 0

And therefore

K = 0

So, its kinetic energy is zero.

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.