what is the definition of negative and positive velocity?

Answer 1

The positives and negatives in velocity are direction. Convention says that upward velocity is positive while downward velocity is negative.
On a surface, convention says that velocity to the right is positive and velocity to the left is negative.

An example: If a car is moving at 3 m/s to the right, that would be +3 m/s. If it stops and goes to the left at 3 m/s, that would be -3 m/s.

Answer 2

Velocity is a vector quantity. A vector quantity is fully described when both magnitude and direction are stated.

Consider a body moving northwards with a given speed. Another body moving southwards with the same speed has negative velocity. Although the magnitude of the velocity (speed) of both bodies is the same, the velocity of the second is negative to the first one.

If the first body is being compared to the second one, the second one would have a positive velocity and the first one would have a negative velocity.

Thus, a body has a negative velocity when it is moving in the opposite direction to another body it is being compared to.

Answer 3

Velocity and speed are different by only direction. Velocity is a vector quantity and direction can be either positive or negative depending on the direction.From the point of a reference one direction is taken as positive and the opposite is taken as negative. I think this is correct.

Answer 4

Velocity is a vector that contains information of the speed
and direction of an object.

The sign indicates the direction of an object.

For instance

traveling to the left could be represented by a negative sign.
traveling to the right could be represented by a positive sign.

The number indicates the speed/rate that an object is traveling at.

Speed is equal to the absolute value of velocity.

Speed is a scalar quantity, meaning that it is just represented by a number.

Answer 5

Velocity has two components, speed and direction. Speed can be
measured in whatever units you like, say miles per hour. Direction is defined
by the person doing the measurement. So, if I define one direction to
be positive I will have a positive velocity when travelling in that
direction. I will have a negative velocity when travelling in the
opposite direction.

Answer 6

Everything in physics is done with respect to a reference frame. Say, for example, that you define a coordinate system such that the positive x-direction is positive motion. Then, you would say that movement toward positive infinity is positive, while any movement toward negative infinity is negative motion. However, you could just as easily say the opposite, that motion along the negative axis is actually positive (for example, if your car was pointing that way, you may CHOOSE to call this positive velocity).

The point is that positive motion is along whatever direction you DEFINE to be positive, and motion in the opposite direction is automatically negative. Everything in physics is done with respect to a chosen reference frame, and as long as you are consistent, it will always work out.

For example, while I am doing engineering calculations, I often consider an object that is falling to be moving in the positive direction, even though up is usually considered positive and down is usually negative. However, I am free to choose otherwise as long as I am consistent throughout my applications, so I try to go with what will make the math easiest for me.

Answer 7

Positive is forwards, and negative is backwards.

Answer 8

You randomly select a direction and call that direction positive.

The opposite direction will be negative.
.

Answer 9

effective speed is once you do your very own homework. detrimental speed is whilst somebody else does it for you. 0 speed is approximately how briskly your getting your homework performed at the same time as playing on the internet. i assume going to hell may be detrimental speed. thank you for the advice...