Define relative speed.?

Question

An example would help also, maybe use it in a sentence so I could understand it better pls?

Answer 1

Relative speed is the difference in the velocities of two objects.

Let's call east the + direction and west the - direction.

If Car A is going +50 mph and Car B is going -50 mph, they have a relative speed of 50 mph - (-50 mph) = 100 mph.

If Car A is going + 50 mph and Car B is going + 50 mph they have a relative speed of 50 mph - 50 mph = 0 mph

Here's a sentence:

A planeful of people moving at 600 mph has a passenger walking forward up the aisle at 2 mph relative to the plane. Relative to the ground, the passenger has a speed of 602 mph.

Answer 2

The speed of an object depends on the reference frame of the observer.

Let's say you are in a car doing 60 mph down the highway.

If you don't look out the window or at the speedometer, you really have no perception of your speed. Everything in the car - a cup of coffee, the head rest, etc. are not moving as far as you are concerned.

You pass a cop on the side of the road. Since he is not in the car, he sees the car, and all the occupants/objects in it, as doing 60 mph.

You pass a car that is doing 40 mph. To the occupants in the other car, you are doing 20 mph, because that is the difference between your two speeds.

Similarly, a car coming directly towards you at 50 mph perceives you coming toward him at 110 mph.

Hope this helps.

Answer 3

Relative speed means that a measured speed is "relative to a frame of reference. For example, if a car is going down the road at 100 miles per hour, it's speed relative to the earth would be hundred miles per hour. The earth is the reference frame. Now, if someone was hovering in space above the earth, they would see the car moving and the earth moving. To get your speed they would add the speed of the car and the earth's speed if you were going the same direction the earth is spinning. This would be the relative speed from their perspective. All speeds are relative to some reference frame. Neither of the two speeds described above would be your true speed. You can keep expanding the reference frames forever to furthur derive your speed. (exampe, earth moves around sun, sun around galaxy, etc).

Answer 4

All speed is relative.

If you were to get up walk toward the cabin while on a commercial aircraft flying at 500 mph, your relative speed to another passenger would be 1 or 2 mph, to some one on the ground, your relative speed is 502 mph! Speed is relative to the observer's reference.

Answer 5

For example, if you and your friend are both walking together at 3 mph, you both are moving at 3 mph relative to the ground but at 0 relative to each other.

If you are driving at 50 mph and oncoming traffic is also traveling at 50 mph, you are traveling at 100 mph relative to each other.

If you use speeds that approach the speed of light, this example will no longer work due to relativity. (Beyond the scope of this answer).

Answer 6

You're in a car, going 80MPH. The police behind you are going at 90 MPH. relative to you, they're going 10 MPH.

Answer 7

velocity that wa calculate from a non inertial frame of refrence i.e. which is in motion with another body whose velocity is to be calculated ia termed as relative velocity.