Impotent Definitions of Motion in a Straight line Chapter 3: Motion in a Straight Line Physics Class 11 solutions are developed for assisting understudies with working on their score and increase knowledge of the subjects. Rectilinear motion, Reference point, Frame of reference, Displacement, Average velocity, Average speed, Instantaneous velocity, Average acceleration, Instantaneous acceleration is solved by our expert teachers. You can get ncert solutions and notes for class 11 chapter 3 absolutely free. NCERT Solutions for class 11 Physics Chapter 3: Motion in a Straight Line is very essencial for getting good marks in CBSE Board examinations
Rectilinear motion
Motion of objects along a straight line is known as rectilinear motion.
Reference point
The point of intersection of three mutually perpendicular axes, labelled as X, Y, and Z axes is called origin (O) and serves as the reference point.
Frame of reference
The coordinates (x, y. z) of an object along with a clock in a system constitutes a frame of reference.
Path length
Path length is a scalar quantity. Total distance covered by object is known as path length.
Displacement
Displacement is a vector quantity. The difference between final and initial position is known as displacement. The magnitude of displacement cannot more than path length.
Let x1 and x2 be the positions of an object at time t1 and t2.
Then its displacement, Δx = x2– x1
If x2> x1, Δx is positive; and if x2< x1,Δx is negative.
Average velocity
Average velocity is defined as the change in position or displacement (Δx) divided by the time intervals (Δt).it is a vector quantity.
[overline v = frac{{{x_2} - {x_1}}}{{{t_2} - {t_1}}} = frac{{Delta x}}{{Delta t}}]
Where x1 and x2 be the positions of an object at time t1 and t2.
The SI unit for velocity is m/s or m s–1
Average speed
Average speed is defined as the total path length travelled by object divided by the total time interval during which the motion has taken place. it is a scalar quantity.
[{ m{Average}};{ m{speed = }}frac{{{ m{Total}};{ m{path}};{ m{length}}}}{{{ m{Total}};{ m{time}};{ m{interval}}}}]
The SI unit for speed is m/s or m s–1
Instantaneous velocity
Velocity of an object at a particular instant is known as instantaneous velocity of that instant. In Instantaneous velocity Δt becomes infinitesimally small.
Instantaneous velocity,${v_{ins}} = mathop {lim }limits_{Delta t o 0} {{Delta x} over {Delta t}} = {{dx} over {dt}}$ .
Instantaneous velocity is the rate of change of position with respect to time, at that instant.
For uniform motion, Instantaneous velocity is the same as the average velocity at all instants.
Average acceleration
The average acceleration aavg over a time interval is defined as the change of velocity divided by the time interval
$$overline a = {{{v_2} - {v_1}} over {{t_2} - {t_1}}} = {{Delta v} over {Delta t}}$$
Where v1 and v2 be the velocity of an object at time t1 and t2.
It is vector quantity.
Instantaneous acceleration
Acceleration of an object at a particular instant is known as instantaneous acceleration of that instant. In Instantaneous acceleration Δt becomes infinitesimally small.
Instantaneous acceleration,${a_{ins}} = mathop {lim }limits_{Delta t o 0} {{Delta v} over {Delta t}} = {{dv} over {dt}}$ .
Instantaneous acceleration is the rate of change of velocity with respect to time, at that instant.
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