Information regarding acceleration

In summary, as long as the acceleration is in the same direction as the velocity, speed will be changing by x meters/second every second. If the acceleration were in the opposite direction then speed would instead be decreasing by x meters/second every second. And, velocity is the change in displacement/time.
  • #1
TT0
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Hello guys,

The units for acceleration is ms-2, does this mean that for every second the speed is increasing by x ms-1?

Also can acceleration be used for speed and velocity since speed is distance/time while velocity is displacement/time?

Thanks
 
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TT0 said:
The units for acceleration is ms-2, does this mean that for every second the speed is increasing by x ms-1?
If the acceleration is in the same direction as the velocity, yes. If the acceleration were in the opposite direction then speed would instead be decreasing by x meters/second every second. If the acceleration were in the perpendicular direction then speed would not be changing at all.

Also can acceleration be used for speed and velocity since speed is distance/time while velocity is displacement/time?
The unit for acceleration are the same as the unit for the rate of change of speed over time. So yes it is perfectly acceptable to use units of acceleration when talking about a rate of change of speed. The term "tangential acceleration" is often used to make it more explicit.
 
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Hello, thanks for replying,

jbriggs444 said:
If the acceleration is in the same direction as the velocity, yes. If the acceleration were in the opposite direction then speed would instead be decreasing by x meters/second every second. If the acceleration were in the perpendicular direction then speed would not be changing at all.

What do you mean by direction? Is it the graph?

Also my understanding of velocity is displacement/time, is this correct?

Thanks
 
  • #4
Velocity is a vector (a quantity with both magnitude and direction), speed is just a magnitude regardeless of direction of propogation. So if you're traveling "forward" with a speed ##y\frac{m}{s}##, and there is an acceleration backwards with magnitude ##x\frac{m}{s^2}## then every second, you will have a change in velocity of ##x\frac{m}{s}## backwards, which means a total change in velocity of ##(y-tx)\frac{m}{s}##, where t is time. Hope this helps.
 
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TT0 said:
Hello, thanks for replying,
What do you mean by direction? Is it the graph?

Also my understanding of velocity is displacement/time, is this correct?

Thanks

If you are traveling in a straight line in one direction only, then essentially speed is the same as velocity. But, there are two cases when you must be careful not to mix the two up:

a) If you travel in a straight line both forwards and backwards, then you have to choose which direction is +ve and which is -ve. Speed is then the magnitude of velocity, which can be positive or negative. If you choose moving to the right as positive, then you would have a velocity of, say, +5m/s if you are moving to the right and -5m/s if you are moving to the left. In both cases the speed is 5m/s.

b) If you are moving in a curve (a circle, for example), then you may be changing both your speed and direction. For example, if you are moving in a circle at constant speed, then you are accelerating. This is because you are constantly changing direction. And, to move in a circle, you need a force to be constantly pushing you inwards. So, in fact, the acceleration (which is also a vector) is directed towards the centre of the circle.

In fact, for any motion, you need to be thinking in terms of velocity, with speed being the magnitude of the velocity. And acceleration being the rate of change of velocity; never the rate of change of speed.

Finally, velocity is the "change in displacement/time", which is the "rate of change of displacement". Think of the circular motion again: the change in displacement is around the edge of the circle.
 
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Ok thanks everyone replying and helping me out. I think I get it.
 

FAQ: Information regarding acceleration

What is acceleration?

Acceleration is the rate at which an object's velocity changes over time. It is a vector quantity, meaning it has both magnitude and direction. In simpler terms, it is the measure of how fast an object is speeding up, slowing down, or changing direction.

How is acceleration calculated?

Acceleration can be calculated using the formula: a = (vf - vi) / t, where a is acceleration, vf is final velocity, vi is initial velocity, and t is time. This formula can be used for both linear and angular acceleration.

What are the units of acceleration?

The standard unit of acceleration is meters per second squared (m/s^2). However, other commonly used units include miles per hour squared (mph/s^2) and feet per second squared (ft/s^2).

What factors affect acceleration?

Acceleration can be affected by various factors, including the force applied to an object, the mass of the object, and the object's initial velocity. Other factors such as air resistance and friction can also affect the acceleration of an object.

What is the difference between acceleration and velocity?

Acceleration and velocity are closely related but are not the same. Velocity is the measure of the speed and direction of an object, while acceleration is the measure of how that velocity is changing. In other words, velocity is the rate of change of displacement, while acceleration is the rate of change of velocity.

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