Scalar and Vector Quantities
What are scalar quantities?
These are physical quantities which are expressed only by their magnitude.
When is a body said to be at rest and when is a body in motion?
A body is said to be at rest if it does not change its position with respect to its immediate surroundings while body is said to be in motion if it changes its position with respect to its immediate surroundings.
Define Distance
It is the total length of the path through which a body moves.
What is the difference between uniform and non-uniform speed?
Uniform speed - a body covers equal distance in equal intervals of time throughout motion. Non-uniform speed - a body covers unequal distances in equal intervals of time.
What is the formula and SI unit of acceleration?
(Change in velocity)/(Time interval)
Metres per second square (ms-2)
What are the parameters to express a scalar quantity completely?
i. Unit in which the quantity is being measured
ii. Numerical value of the quantity
What is “one-dimensional motion”?
When a body moves along a straight line path its motion is said to be one dimensional motion.
Define the magnitude of Displacement
It is the shortest distance from the initial to the final position of a body
What is the formula for instantaneous speed?
(Distance travelled in a short time interval)/(Time interval)
What is retardation?
Retardation takes place when the velocity of the body decreases over time.
What are vector quantities?
These physical quantities require the magnitude as well as the direction to express them.
Give two other names for one-dimensional motion
Motion in a straight line, Rectilinear motion
Give 1 difference between distance and displacement (other than definition)
i. Distance is always positive
Displacement may be positive or negative depending on direction
ii. Distance is a scalar quantity, displacement is a vector quantity
Speed is a _________ quantity while velocity is a ________ quantity
Scalar, vector
Which of the quantities, velocity or acceleration determine the direction of motion?
Velocity
What are all the parameters to express a vector quantity completely?
i. Unit
ii. Numerical value of the quantity
iii. Direction
Give two examples of one-dimensional motion
Train on a straight track, a stone falling down vertically
What is the SI and CGS unit of displacement?
Metres (m), centimetres (cm)
What is the formula for average velocity?
(Displacement)/(Total time taken)
Differentiate between uniform and variable acceleration
Uniform - When changes in velocity takes place in equal intervals of time
Variable - If changes in velocity is not in the same in the same intervals of time
Select the scalar and vector quantities from the following:
mass, length, momentum, force
Scalar - Mass, length
Vector - Momentum, force
How do you represent a one-dimensional motion on a graph
It is represented as a straight line parallel to the X-axis, if the X-axis represents the direction of the motion
__________ can be zero even if _________ isn’t zero.
Displacement, distance
Mention 3 differences between Speed and Velocity
i. Speed is a scalar quantity,
Velocity is a vector quantity
ii. Speed is always positive since direction is not considered,
Velocity may be positive or negative depending on the direction of motion.
iii. After 1 round of a circular path, average speed is not zero
After completing each round of a circular path, average velocity is zero
iv. Speed is the distance travelled per second by a moving object
Velocity is the distance travelled per second by a moving object in a particular direction
Define Acceleration due to gravity.
When a body falls freely under gravity, the acceleration produced in the body due to the earth’s gravitational attraction is called acceleration due to gravity.