Answer:

Explanation:
As we know by work energy theorem that work done by all forces is equal to change in kinetic energy
So we know that
![W_f + W_g = \frac{1]{2}mv_f^2 - \frac{1}{2}mv_i^2](https://tex.z-dn.net/?f=W_f%20%2B%20W_g%20%3D%20%5Cfrac%7B1%5D%7B2%7Dmv_f%5E2%20-%20%5Cfrac%7B1%7D%7B2%7Dmv_i%5E2)
so we know that




now we have



The quantity that has a magnitude of zero when the ball is at the highest point in its trajectory is
the vertical velocity.
In fact, the motion of the ball consists of two separate motions:
- the horizontal motion, on the x-axis, which is a uniform motion with constant velocity

, where

- the vertical motion, on the y-axis, which is a uniformly accelerated motion with constant acceleration

directed downwards, and with initial velocity

. Due to the presence of the acceleration g on the vertical direction (pointing in the opposite direction of the initial vertical velocity), the vertical velocity of the ball decreases as it goes higher, up to a point where it becomes zero and it reverses its direction: when the vertical velocity becomes zero, the ball has reached its maximum height.
Answer:
Explanation:
Moving a magnet might cause a change in the magnetic field going through the solenoid. Whether or not it will change depends on the movement.
According to Faraday's law of induction a voltage is induced in a coil by a change in the magnetic flux. Magnetic flux is defined as the dot product of the magnetic field (a vector field) by the area enclosed by a loop of the coil.

The voltage is induced by the variation of the magnetic flux:

Where
ε: electromotive fore
N: number of turns in the coil
ΦB: magnetic flux
Moving the magnet faster would increase the rare of change of the magnetic flux, resulting in higher induced voltage.
Turning the magnet upside down would invert the direction of the magnetic field, reversing the voltage induced.
You can do 50 and 10 and carry the 30 and it would be in the same power so you’ll have the same energy