What is the difference between speed , velocity and acceleration?

Answer 1

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Definitions:............................…

Speed or Velocity?

Speed is the rate of motion, or the rate of change of position. It is expressed as distance moved (d) per unit of time(t). Speed is a scalar quantity with dimensions distance/time. Speed is measured in the same physical units of measurement as velocity, but does not contain an element of direction. Speed is thus the magnitude component of velocity. Velocity contains both the magnitude and direction components.

Common speeds of moving objects

For human beings, an average walking speed is about 3 mph (~5 km/h, 1.39m/s),
The speed of long distance jogging for average persons is about 6 mph (~10 km/h, 2.7 m/s).
Top athletic sprinters can run at 23.03 mph (~36.85 km/h, 10.24 m/s) within a short distance such as a 200 meters dash.
Cycling can average 12 mph (~20 km/h, 5.56 m/s)
Car can average 65 mph (~104 km/h, 28.9 m/s ) on highway
A 747 Airplane has an average speed 565 mi/hr

Acceleration

Acceleration, (symbol: a) is defined as the rate of change of velocity. It is thus a vector quantity with dimension length/time². In SI units, acceleration is measured in meters/second².

To accelerate an object is to change its velocity, which is accomplished by altering either its speed or direction (like in case of uniform circular motion) in relation to time. Acceleration can have positive and negative values. Any time that the sign (+ or -) of the acceleration is the same as the sign of the velocity, the object will speed up. If the signs are opposite, the object will slow down. Acceleration is a vector quantity. When either velocity or direction changes, there is acceleration (or deceleration).

To accelerate an object requires the application of a force.

Speed, Velocity, and Acceleration............................…

Along with displacement, velocity and acceleration round out the holy trinity of kinematics. As you’ll see, all three are closely related to one another, and together they offer a pretty complete understanding of motion. Speed, like distance, is a scalar quantity that won’t come up too often on SAT II Physics, but it might trip you up if you don’t know how to distinguish it from velocity.

Source(s):

http://www.edinformatics.com/math_scienc…
http://www.sparknotes.com/testprep/books…
http://www.physicsforums.com/archive/ind…

Answer 2

I think speed and velocity are the same and acceleration is the rate at which you build velocity.

Answer 3

speed has no direction
velocity is speed with direction
the derivative of velocity is acceleration

Answer 4

well acceleration is the change in distance per unit time n velocity is the rate of change of displacement
n speed is the change in distance per time

Answer 5

speed of a body is distance travelled by it per unit time.
it is scalar quantity i.e. having only magnitude

velocity of a body is the distance travelled by it per unit time in given direction.
it is vector quantity(having direction)

acceleration is defined as rate of change of its velocity with time.
its vector quantity !

Answer 6

speed is the change in displacement (or position) per unit time

velocity is a vector quantity which has a speed and direction

acceleration, another vector, is the change in velocity over time

Velocity always has a speed and direction. Acceleration, therefore, can result from a change in either direction or speed.

Answer 7

Along with displacement, velocity and acceleration round out the holy trinity of kinematics.Speed, like distance, is a scalar quantity that won’t come up too often on SAT II Physics, but it might trip you up if you don’t know how to distinguish it from velocity.
As distance is to displacement, so speed is to velocity: the crucial difference between the two is that speed is a scalar and velocity is a vector quantity. In everyday conversation, we usually say speed when we talk about how fast something is moving. However, in physics, it is often important to determine the direction of this motion, so you’ll find velocity come up in physics problems far more frequently than speed.

Answer 8

Speed is the rate at which distance is covered by a moving object. The direction of movement is not important. If the object moves on a curved path from A to B, straight line distance from A to B may be less than the distance covered, but for measuring speed, actual distance covered along the curved line Ab divided by time gives the speed. Speed is a scalar quantity meaning that it has magnitude only and no direction.

Velocity is the rate of change of displacement of the moving object. When an object goes from A to B on a curved path, magnitude of velocity is the straight line distance from A to B divided by time. This is the magnitude of average velocity from A to B. Moreover, velocity is a vector quantity meaning that it has both magnitude as well as direction. So, simply specifying magnitude does not give the velocity. The direction from A to B should also be given to fully specify velocity. If the object covers distance 25 m on a curved line from A to B in 5 s, its speed is 5m/s. If the straight line distance from A to B is 15 m, its average velocity is 3 m/s directed from A to B.

Acceleration is the rate of change of velocity. As the velocity is a vector quantity, so is the acceleration. If the velocity of an object at a certain instant is 5 m/s in a given direction and is 20m/s after 3 s in the "same" direction, then, the average acceleration of the object is (20 - 5)/3 = 5 m/s² in the same direction. If the direction of velocity at the end of 3 seconds is different, then the difference in velocity cannot be taken arithmetically, but a vecor difference has to be taken. The resultant average acceleration may have direction different from both the intial and final velocity.

Answer 9

speed is the distance travelled by a moving object in one unit time.
Velocity is the distance travelled by a body n per unit time in a given direction.
Accelaration is the rate change of its velocity in time.

Answer 10

Speed is a scalar quantity. It is the distance covered divided by time taken (in any direction). It has magnitude only and doesn't specify in which direction the object is traveling whereas velocity has both magnitude and direction. Velocity is a vector having the same magnitude as speed but its direction is always specified.
Acceleration is the rate of change of velocity. It is the rate at which the velocity increases or decreases.

Answer 11

klesh1_koluu

Source(s):

mknu

Answer 12

speed is a scalar quantity ,it has magnitude but no direction , it is used to measure the distance travelled by a body in per unit time whereas velocity is a vector quantity , it has both magnitude and direction ,it is used to measure the displacement of a body per unit time .but both have the same unit foir measurment. and acceleration is the change in velocity per second.

Source(s):

from 11th textbook

Answer 13

Speed is a scalar quantity , that is, dirrection is not taken into account.
Velocity is a vector quantity, that is dirrection is taken into account.
Acceleration is the derivative of velocity and measures change in velocity with respect to time (also a vector)

Answer 14

speed=rate of change of motion(d/t)
velocity=rate of change of displacement(d/t in particular direction)
acceleration=rate of change of velocity(v-u/t)

Answer 15

Speed = distance/time
Velocity = displacement/time
Acceleration = Velocity/time= displacement/time/time
= Displacement/time^2

Answer 16

speed is basically distance covered in the given time wherein dirn is not specified
velocity is displacement traversed in a given time in a given direction
speed does not obey vector laws of addition and hence is a scalar while velocity is a vector
accelration is velocity/time and it is a vctor again

Answer 17

PLEASE STUDY 'IT',; Physics.