Answer:
Work done on an object is equal to
FDcos(angle).
So, naturally, if you lift a book from the floor on top of the table you do work on it since you are applying a force through a distance.
However, I often see the example of carrying a book through a horizontal distance is not work. The reasoning given is this: The force you apply is in the vertical distance, countering gravity and thus not in the direction of motion.
But surely you must be applying a force (and thus work) in the horizontal direction as the book would stop due to air friction if not for your fingers?
Is applying a force through a distance only work if causes an acceleration? That wouldn't make sense in my mind. If you are dragging a sled through snow, you are still doing work on it, since the force is in the direction of motion. This goes even if velocity is constant due to friction.
Explanation:
Inertia is a term that qualitatively describes the ability of a substance to resist changes in its state of motion, while mass gives a quantitative value for inertia
Answer:
The maximum electric power output is 
Explanation:
From the question we are told that
The capacity of the hydroelectric plant is 
The level at which water is been released is 
The efficiency is
0.90
The electric power output is mathematically represented as
Where
is the potential energy at level h which is mathematically evaluated as

and
is the potential energy at ground level which is mathematically evaluated as


So
here 
where V is volume and
is density of water whose value is 
So

substituting values


The maximum possible electric power output is

substituting values


Answer:
The unbalanced force that caused the ball to stop was friction
Explanation:
As Newton's second law states, the acceleration of an object is proportional to the net force applied on the object:

therefore, in order to move at constant speed, an object should have a net force of zero (balanced forces) acting on it.
In this case, the ball slows down and eventually comes to a stop: it means that the ball is decelerating, so there are unbalanced forces (net force different from zero) acting on it. The unbalanced force acting on the ball is the friction: friction is a force against the motion of the object, which is due to the contact between the surface of the ball and the surface of the street, and this force is responsible for slowing down the ball.
A big part of the reason that mirrors are seldom if ever used to generate
electricity is the simple fact that there is no way to generate electricity using
mirrors. They are as useless for the purpose as smoke is, although there are
those who have used both items simultaneously to create the impression that
they have succeeded in that attempt.