I love science! if you need any more help let me know i cant guarantee i can help but i will try!
The correct answer is "Some substances must be dissolved in water before they can be used".
Answer:
Acceleration, 
Explanation:
It is given that,
Speed of electron, 
Charge on an electron, 
Mass of electron, 
Magnetic field, 
Magnitude, 
Magnetic force is given by :
Also, F = ma
So, the acceleration of the electron is 
. Hence, this is the required solution.
Answer:
All the three quantities will have non zero joules.
Explanation:
At the initial position of rest the system will have only gravitational potential energy while the other 2 quantities will be zero.
when the system reaches a height (y-h) only kinetic energy will be zero while the other 2 quantities will be non zero
At the position of (y-h/2) all the 3 quantities will be non zero.
Answer:
15 meters
Explanation:
The inicial energy of the ball is just potencial energy, and its value is:
E = m * g * h = m * g * 20,
where m is the ball mass, and g is the value of gravity.
In the moment that the ball strickes the ground, all potencial energy transformed into kinetic energy, and 25% of this energy is lost, so the total energy at this moment will be:
E' = 0.75 * E = 0.75 * m * g * 20 = 15*m*g
This kinetic energy will make the ball goes up again, and at the maximum height, all kinetic energy is transformed back into potencial energy.
So, as the mass and the gravity are constants, we can calculate the height the ball will reach:
E' = m*g*h = 15*m*g -> h = 15 meters
