Explanation:
Given that,
The mass of rock, m = 2.35-kg
It was released from rest at a height of 21.4 m.
(a) The kinetic energy is given by : 
As the rock was at rest initially, it means, its kinetic energy is equal to 0.
(b) The gravitational potential energy is given by : 
It can be calculated as :

(c) The mechanical energy is equal to the sum of kinetic and potential energy such that,
M = 0 J + 492.84 J
M = 492.84 J
Hence, this is the required solution.
I think it’s output because output work is work done by a machine
Answer:
D) 8
Explanation:
Due to the octet rule the most stable atoms will have 8 valence electrons.
B. Please mark me the brilliantest pls
Answer: DC Current
Explanation:
Battery is a source of constant potential difference and it will create a constant voltage across any conductor
due to this constant voltage difference the current in this conductor will remain constant
So here since the voltage across the conductor is constant so we can say that current in the conductor will remain constant and hence this is known as DC current.
While for variable current in direction and magnitude is to be obtained only when the conductor is connected with AC voltage source as we know that AC voltage is variable with magnitude and direction both
A battery is the power source for DC type of current. A battery is a source of constant potential difference that produces a constant current unlike in AC source where the voltage and hence the current changes its polarity continuously.Hence, the current produced by battery is direct current and not Alternating current.
Hope this helps........ Stay safe and have a Merry Christmas!!!!!! :D