when is an object said to be in a state of rest?

if the object does not change its position with respect to its surroundings with time.

when is an object in motion?

if the object changes its position with respect to its surroundings with time

why are rest and motion relative terms?

an object may seem to be in motion with respect to some objects and at rest with respect to others.

translatory motion

all parts of a moving object move the same distance at the same time.

rectilinear motion

a type of translatory motion where the body moves along a straight path

curvilinear motion

a type of translatory motion where the body moves along a curved path. Ex: discus in discus throw, train moving on a curved track.

circulatory motion

The body moves around a circular path such that its distance from the centre is always fixed and cannot change. Ex: the moon in its orbit around the Earth

rotatory motion

The body rotates on its axis. The part near the axis travels a lesser distance than the part far from the axis.

oscillatory motion

The body moves to and fro about its mean position.

simple pendulum components

it consists of a small, heavy mass [bob], a rigid support, and a string

one oscillation

one complete to and fro motion about its mean position

time period

time taken to complete one oscillation

vibratory motion

type of oscillatory motion in which only one part of the body moves to and fro about its mean position. it produces sound.

periodic motion

A body repeats its motion after a fixed interval. Ex: rotation of the Earth around the Sun, rotation of the Earth around its own axis

non- periodic motion

a body does not repeat its motion after a fixed interval of time. Ex: a heartbeat, movement of our hands while writing

multiple motion

If a body exhibits more than one kind of motion at a time. Ex: motion of the earth on its orbit[rotatory and curvilinear], a vehicle moving on a straight road{rolling, linear, rotatory and circulatory}, motion of a drill drilling into smth[rotatory and translatory]

rolling motion

rotatory and translatory motion combined. exhibited in vehicles on a road.

random motion

when an object randomly changes its motion without a pattern or a fixed interval.

distance

total length of a path covered by an object, irrespective of direction. It is a scalar quantity. either positive or 0.

displacement

The shortest distance between the initial and final position of an object. It is a vector quantity. it can be negative[if the object moves in the opposite direction instead of forward], positive, or 0[returns to original position]

scalar quantity

quantity with only magnitude and no direction. Ex: distance, speed, volume

vector quantity

quantity with both magnitude and direction. Ex: velocity, displacement, weight

uniform motion

a body covers equal distances in equal intervals of time without changing direction.

non- uniform motion

a body covers unequal distances in equal intervals of time. even if it covers equal distances in equal intervals of time, if it changes its direction, it is non- uniform.

speed

distance _________ SI unit- m|s time

velocity

displacement ______________ SI unit- m|s time

mass

quantity of matter contained in an object.

SI unit of mass

kg

does mass depend on location?

no, it is a constant quantity that does not depend on position or location.

measurement of mass

done using a beam balance or a physical balance.

weight

force of attraction of the earth acting on a body to pull it down to its center. weight= mass x acceleration due to gravity{9.8 or 10}

SI unit

newton

measurement of weight

done using a spring balance. there is a hook on which the object is hung. the object pulls the hook, which is connected to a spring, down and the spring elongates. then, a pointer points to the value.

does weight depend on location?

yes, its value changes based on the gravity of the place.

direction of weight

it always works in a vertically downward direction

can weight be 0?

yes, if there is no gravity in that place.

can mass be 0?

no, it can never be zero.