When an atom is involved in a nuclear reaction:

its electrons may change but its nucleus remains the
same

its nucleus changes

it may change from one element to another

it must remain the same element

Please help!

"an open tank has the shape of a right circular cone. the tank is 6 feet across the top and 5 feet high. how much work is done in emptying the tank by pumping the water over the top edge? note: the density of water is 62.4 lbs per cubic foot."

Standing side by side ,you and a friend step off a bridge at different times and fall for 1.6s to the water below. your friend goes first, and you follow after he has dropped a distance of 2.0m. when your friend hits the water, is the seperation between the two of you 2.0m or more than 2.0m? verify your answer with a calculation.

Need asap ‼️ 20 pts which gravitational force field diagram is drawn correctly? (answers in pictures below)