MOTION IN A STRAIGHT LINE
Frequently Asked Questions
Motion is the change in position of an object with time relative to a chosen reference point.
It is motion where an object moves along a single straight path, also called one-dimensional motion.
A reference point is a fixed point relative to which the position and motion of an object are described.
Yes, rest and motion depend on the observer’s frame of reference.
Distance is the total length of the actual path travelled by an object, irrespective of direction.
Displacement is the shortest straight-line distance between initial and final positions, with direction.
Because it has both magnitude and direction.
Yes, when an object returns to its starting point.
Speed is the rate at which distance is covered with time.
Velocity is the rate of change of displacement with time and includes direction.
Speed is scalar; velocity is vector and depends on direction.
Average speed is total distance travelled divided by total time taken.
Average velocity is total displacement divided by total time.
When motion is along a straight line without change in direction.
Velocity of an object at a particular instant of time.
As the derivative of displacement with respect to time: \( v = \frac{dx}{dt} \).
The magnitude of instantaneous velocity.
Acceleration is the rate of change of velocity with time.
Yes, it has both magnitude and direction.
Acceleration that remains constant with time.
Acceleration that changes with time.
Acceleration acting opposite to the direction of velocity, reducing speed.
metre per second squared \(m\ s^{-2}\).
\(( v = u + at ),\ ( s = ut + \frac{1}{2}at^2 ),\ ( v^2 = u^2 + 2as \).
Only for straight-line motion with uniform acceleration.
Velocity changes linearly with time under constant acceleration.
Total displacement due to initial velocity and acceleration.
It directly connects velocity and displacement.
Motion of an object under gravity alone, neglecting air resistance.
Constant downward acceleration experienced by freely falling objects.
Approximately \( 9.8 , \text{m s}^{-2} \).
No, all objects fall with the same acceleration if air resistance is ignored.
Velocity becomes zero, but acceleration remains non-zero.
Yes, for motion under gravity without air resistance.
Distances covered in successive equal time intervals are in the ratio 1:3:5:7…
For motion starting from rest with uniform acceleration.
Time taken by a person to respond to a stimulus.
Distance travelled during reaction time before braking starts.
Sum of reaction distance and braking distance.
Because braking distance is proportional to the square of speed.
Distance covered after brakes are applied until the vehicle stops.
It ensures correct mathematical representation of direction.
Velocity of the object.
Acceleration of the object.
Displacement.
Zero acceleration and constant velocity.
Yes, in uniform motion.
Yes, at the highest point of vertical motion.
One-dimensional motion with uniform or non-uniform acceleration.
It forms the foundation for understanding all types of motion in physics.
