Tiêu đề Chapter - 1 Motion.pdf ✅

ChemContent ● If ‘s’ is the distance travelled by a body in time ‘t’, then its speed ‘v’ ’ is given as v = s\t ● Speed of a body is a scalar quantity. It can be zero or positive but can never be negative. ● If a body covers equal distances in equal time intervals, howsoever small the intervals may be, then it is said to have uniform speed (or constant speed). ● If a body covers unequal distances in equal time intervals, however small the intervals may be, then it is said to have non-uniform speed (or variable speed). ● For bodies moving with non-uniform speed, we describe the rate of motion in terms of their average speed. Velocity ● Velocity of a body is defined as the distance travelled by the body in unit time in a given direction. ● The SI unit of velocity is the same as that of speed, i.e. metre/second (m/s). where v is velocity and s is displacement of the body in time t. ● Velocity of a body is a vector quantity. It can be positive, negative or zero. ● A body is said to be moving with uniform velocity (or constant velocity) if it travels along a straight line, covering equal distances in equal intervals of time, howsoever small these intervals may be. ● A body is said to be moving with non-uniform velocity (or variable velocity) if it covers unequal distances in a particular direction in equal intervals of time or if the direction of motion of the body changes. ● When the velocity of a body is changing at a uniform rate over a period of time, the average velocity for that time period is given by the arithmetic mean of the initial and final velocity of the body.