How do I calculate acceleration and magnitude in physics?

[LanaStClair]

New at Physics, PLEASE HELP :)

Hello, I'm in 8th grade advanced Science, we just started physics but I'm very confused. Can anybody help me on how to calculate acceleration and magnitude? Thanks This is NOT homework, I am just trying to study for an exam tomorrow.

 

[spacelike]

Well magnitude is a general property of vectors. Not just acceleration.
For example. velocity is a vector, the difference between "velocity" and "speed" is that "velocity" has a magnitude and a direction, whereas "speed" only has magnitude.

So "magnitude" is like the length of the vector. Another way to look at is is that if you are doing 1-dimensional problems (which you probably are) then your "vectors" are basically just a single number that can be positive or negative, then "magnitude" is like the absolute value.As for acceleration, just think of it as the change in velocity over time.
$$a=\frac{\Delta v}{\Delta t}=\frac{v_{f}-v_{i}}{\Delta t}$$

 

[GrantB]

Hello :)

Acceleration is a rate of change of velocity, where velocity is a rate of change of position.

If I run in a 100m race, and finish in 10 seconds, my velocity is how fast I go from beginning to end. In this case it is:

$v = \frac{finish-start}{time} = 10m/s$

In this case, the start is the x=0 position, and finish is the x=100 position.

Acceleration is similar to this.

If I start by going 5m/s and end at 15m/s, then my acceleration is:

$a = \frac{final velocity - initial velocity}{time} = \frac{15m/s-5m/s}{10s} = 1m/s^2$

Now, all of these are averages for the given example, and I randomly chose numbers.

Also, these are all magnitudes. If I were to attach a direction to the magnitude, it would become a vector.

Hope this helps.

 

[NascentOxygen]

While a body is undergoing a change in speed, or even just a change in direction, then it is accelerating (or decelerating).

Only if it is traveling at a constant speed AND in a straight line is it NOT accelerating.

Something going around and around on a circular path at a constant speed is constantly accelerating, since for no time interval is it seen to be traveling in a straight line.

 

[rwisz]

Hi there! Don't worry, physics can be confusing at first but with practice and understanding, it can become easier. Acceleration is the rate of change of velocity over time, and it is calculated by dividing the change in velocity by the change in time. The formula is a = (vf - vi)/t, where vf is the final velocity, vi is the initial velocity, and t is the time interval. Magnitude, on the other hand, refers to the size or amount of a quantity. In physics, it is often used to describe the size of a vector, which is a quantity that has both magnitude and direction. To calculate the magnitude of a vector, you can use the Pythagorean theorem, where the magnitude is equal to the square root of the sum of the squares of its components. I hope this helps, and good luck on your exam tomorrow!