Question

what is the definitions of speed,rest,types of motions ,slow motion,fast motion,average speed, distance,displacement, velocity,acceleration,decelaration for 7th class

Answer 1

Speed
Speed is the distance traveled per unit of time. It is how fast an object is moving. 

Rest
Rest (physics) ... Rest is a state inphysics that refers to an object being stationary relative to a particular frame of reference or another object; when the position of a body with respect to its surroundings does not change with time it is said to be "at rest".

Types Of Motions
These four are rotary, oscillating, linear and reciprocating.

Slow Motion
Slow motion (commonly abbreviated as slo-mo or slow-mo) is an effect in film-making whereby time appears to be slowed down. ... Typically this style is achieved when each film frame is captured at a rate much faster than it will be played back. When replayed at normal speed, time appears to be moving more slowly.

Fast Motion
Action that appears to move faster than normal on the screen, accomplished by filming the action at less than normal speed in the camera and then projecting it at normal speed.

Average Speed
The average speed of an object is the total distance traveled by the object divided by the elapsed time to cover that distance. It's a scalar quantity which means it is defined only by magnitude. A related concept, average velocity, is a vector quantity.

Distance
The length of the space between two points

Displacement
Distance is a scalar quantity that refers to "how much ground an object has covered" during its motion. Displacement is a vector quantity that refers to "how far out of place an object is"; it is the object's overall change in position.

Velocity
The speed of something in a given direction.

Acceleration
In physics, acceleration is the rate of change of velocity of an object with respect to time. 

Deceleration
Deceleration is the opposite of acceleration. It is the rate at which an object slows down. Deceleration is the final velocity minus the initial velocity, with a negative sign in the result because the velocity is dropping.

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