How acceleration is calculated in words

If the velocity and time is given acceleration is calculated  by the formula Acceleration = velocity by time

If the Force and mass of an object is given the acceleration is calculated by the formula Acceleration = Force ÷ mass

Explanation:

if the object is changing the velocity then the object is accelerating. So Acceleration = Velocity by time  

Unit of acceleration = meter per second (m/s) in  SI units.

Dividing distance by time is same as dividing distance by the square of time So acceleration = meter per second square (m/s²)

Force (F) is  Mass (m) times acceleration (a)

F = ma

so Acceleration = Force ÷ mass

c) up is the direction the magnetic force is acting on the charge.