Quick Review Flashcards - Click to flip and test your knowledge!
Question
What is the definition of a physical quantity?
Answer
A quantity that can be measured.
Question
Which two parameters are needed to completely express a scalar quantity?
Answer
The unit of measurement and the numerical value of the quantity.
Question
Term: Scalar quantity
Answer
Definition: A physical quantity expressed only by its magnitude. Example: Mass ($5.0\,kg$).
Question
List three parameters required to express a vector quantity completely.
Answer
Numerical value, unit, and direction.
Question
How are vector quantities symbolically represented in writing?
Answer
By an English letter with an arrow above it (e.g., $\vec{v}$) or by a bold English letter (e.g., $\mathbf{v}$).
Question
In vector notation, what does a negative sign typically imply?
Answer
The reverse or opposite direction.
Question
Give three examples of scalar quantities mentioned in the text.
Answer
Mass, length, and time.
Question
Give three examples of vector quantities mentioned in the text.
Answer
Displacement, velocity, and acceleration.
Question
Under what condition is a body said to be at rest?
Answer
If it does not change its position with respect to its immediate surroundings.
Question
Why is 'rest' considered a relative term rather than an absolute one?
Answer
An object may be at rest relative to one observer but in motion relative to another (e.g., a tree relative to a person on a platform vs a moving train).
Question
When can a moving body be assumed to be a 'point particle'?
Answer
When the distance travelled is much larger than the size of the body.
Question
What defines one-dimensional motion (rectilinear motion)?
Answer
Motion of a body along a straight line path.
Question
Term: Distance
Answer
Definition: The total length of the path along which a body moves. Example: The actual path length taken from point $A$ to point $B$.
Question
What is the S.I. unit of distance and displacement?
Answer
Metre ($m$).
Question
What is the C.G.S. unit of distance and displacement?
Answer
Centimetre ($cm$).
Question
Term: Displacement
Answer
Definition: The shortest distance from the initial position to the final position of a body in a specific direction.
Question
How does the magnitude of displacement relate to the distance travelled?
Answer
The magnitude of displacement is either equal to or less than the distance.
Question
Under what specific condition is the magnitude of displacement equal to the distance?
Answer
When the motion is in a fixed direction along a straight line.
Question
Can displacement be zero if the distance travelled is non-zero?
Answer
Yes, if the body returns to its starting point after travelling.
Question
The rate of change of distance with time is defined as _____.
Answer
Speed.
Question
What is the formula for calculating speed $v$?
Answer
$v = \frac{S}{t}$, where $S$ is distance and $t$ is time.
Question
What is the S.I. unit of speed?
Answer
Metre per second ($m\,s^{-1}$).
Question
Define uniform speed.
Answer
When a body covers equal distances in equal intervals of time throughout its motion.
Question
What type of speed is measured by the speedometer of a vehicle?
Answer
Instantaneous speed.
Question
State the formula for average speed.
Answer
$\text{Average speed} = \frac{\text{Total distance travelled}}{\text{Total time taken}}$.
Question
Term: Velocity
Answer
Definition: The distance travelled per second by a body in a specified direction.
Question
How does velocity differ from speed in terms of quantity type?
Answer
Speed is a scalar quantity, while velocity is a vector quantity.
Question
Under what two conditions are two bodies said to be moving with the same velocity?
Answer
If they move with the same speed and in the same direction.
Question
Define uniform velocity.
Answer
When a body travels equal distances in a particular direction in equal intervals of time.
Question
What are the two ways the velocity of a body can change (variable velocity)?
Answer
By a change in its magnitude (speed), its direction, or both.
Question
Why is the motion of a body in a circular path at constant speed considered variable velocity?
Answer
Because the direction of motion changes continuously at every point.
Question
State the formula for average velocity.
Answer
$\text{Average velocity} = \frac{\text{Displacement}}{\text{Total time taken}}$.
Question
Is it possible for the average velocity of a body to be zero even if its average speed is not?
Answer
Yes, if the body returns to its initial position, displacement is zero.
Question
The rate of change of velocity with time is defined as _____.
Answer
Acceleration.
Question
What is the S.I. unit of acceleration?
Answer
Metre per second square ($m\,s^{-2}$).
Question
State the mathematical formula for acceleration $a$ using initial velocity $u$ and final velocity $v$.
Answer
$a = \frac{v - u}{t}$.
Question
What is retardation (or deceleration)?
Answer
Negative acceleration, occurring when velocity decreases with time.
Question
What does a positive or negative sign for acceleration indicate in straight-line motion?
Answer
Whether the velocity is increasing (positive) or decreasing (negative) with time.
Question
Define uniform acceleration.
Answer
When equal changes in velocity take place in equal intervals of time.
Question
What is the acceleration produced in a body due to Earth's gravitational attraction called?
Answer
Acceleration due to gravity ($g$).
Question
What is the average value of $g$ on the Earth's surface?
Answer
$9.8\,m\,s^{-2}$ (or approximately $10\,m\,s^{-2}$).
Question
How does the sign of $g$ change based on the direction of vertical motion?
Answer
It is $+g$ when falling downwards (velocity increases) and $-g$ when projected upwards (velocity decreases).
Question
Does the value of $g$ depend on the mass of the falling body?
Answer
No, it is independent of the mass of the body.
Question
What physical quantity is represented by the slope of a displacement-time graph?
Answer
Velocity.
Question
In a displacement-time graph, what does a straight line parallel to the time axis represent?
Answer
The body is stationary (at rest).
Question
If a displacement-time graph is a straight line inclined to the time axis, what does this indicate?
Answer
The body is moving with uniform velocity.
Question
What does a negative slope in a displacement-time graph represent?
Answer
The body is returning towards the starting (or reference) point.
Question
Why can a displacement-time graph never be a straight line parallel to the displacement axis?
Answer
It would mean displacement increases infinitely without any increase in time (infinite velocity).
Question
In a displacement-time graph, what does a curve represent?
Answer
Motion with non-uniform (varying) velocity.
Question
What physical quantity is represented by the slope of a velocity-time graph?
Answer
Acceleration.
Question
What is represented by the area enclosed between a velocity-time graph and the time axis?
Answer
Displacement.
Question
In a velocity-time graph, what does a straight line parallel to the time axis represent?
Answer
Motion with uniform velocity (zero acceleration).
Question
What does a straight line inclined to the time axis with a positive slope on a velocity-time graph represent?
Answer
Uniform acceleration.
Question
What does a straight line inclined to the time axis with a negative slope on a velocity-time graph represent?
Answer
Uniform retardation.
Question
How is the total distance travelled calculated from a velocity-time graph?
Answer
By adding the areas under the curve numerically without regard to the sign of displacement.
Question
What information is obtained from the area enclosed between an acceleration-time graph and the time axis?
Answer
The change in speed (or velocity) of the body.
Question
For a body falling freely from rest, displacement $S$ is directly proportional to the _____ of time $t$.
Answer
Square ($S \propto t^2$).
Question
State the first equation of uniformly accelerated motion.
Answer
$v = u + at$.
Question
State the second equation of uniformly accelerated motion.
Answer
$S = ut + \frac{1}{2}at^2$.
Question
State the third equation of uniformly accelerated motion.
Answer
$v^2 = u^2 + 2aS$.