Chapter Questions
Two hour is equal to __ seconds.
The motion of molecules in a solid is an example for _ motion.
One millisecond is _ part of a second.
A body moving with a velocity of $10 \mathrm{~m} \mathrm{~s}^{-1}$ increases its velocity to $20 \mathrm{~m} \mathrm{~s}^{-1}$ in $2 \mathrm{~s}$. Then the rate of change in velocity is _
A car moves with a constant velocity, its average velocity is equal to its _
The time period of a simple pendulum depends on its _
By taking suitable example, describe how a distance-time graph is plotted.$$\begin{array}{ccc}\hline \text { S. No. } & \text { Time (s) } & \text { Distance (m) } \\\hline 1 & 0 & 0 \\2 & 1 & 5 \\3 & 2 & 10 \\4 & 3 & 15 \\5 & 4 & 20 \\6 & 5 & 25 \\7 & 6 & 30 \\\hline\end{array}$$
A body moves with uniform speed of $\mathrm{u} \mathrm{m} \mathrm{s}^{-1}$ towards east, then the body is said to possess _ velocity.
The time taken by the bob of a simple pendulum of time period $(\mathrm{T})$ to move from one extreme position to other extreme position is equal to _
Choose the correct statement:(1) The magnitudes of speed and velocity are same when a body travels in a straight line path.(2) Average speed of a moving body can be equal to zero, but its average velocity cannot be equal to zero.(3) To describe the velocity, direction is necessary.(4) Both (1) and (3)
The ratio of unit of acceleration and velocity gives unit of the physical quantity _(1) time(2) frequency(3) amplitude(4) speed
Unit of speed is _(1) $\mathrm{m} \min ^{-1}$(2) $\mathrm{km} \mathrm{h}^{-1}$(3) $\mathrm{km} \mathrm{s}^{-1}$(4) All the above
The motion of a body is depicted graphically as shown in the figure, then the average speed of the bo is $\mathrm{m} _\mathrm{s} ^{-}$(1) $\frac{3}{4}$(2) $\frac{9}{8}$(3) $\frac{4}{3}$(4) $\frac{8}{9}$
The speed of the tip of a second hand of length $5 \mathrm{~cm}$ of a clock is $\mathrm{m} \mathrm{s}^{-1}$(1) 1(2) 60(3) $5.3 \times 10^{-3}$(4) $3.4 \times 10^{-5}$
The time period of a pendulum is independent of(1) length of the pendulum(2) mass of the bob(3) shape of the bob(4) Both (2) and (3)
The distance between two stations is $20 \mathrm{~km}$. If a train moves with a constant speed of $60 \mathrm{~km} \mathrm{~h}^{-1}$, then the time taken by the train to reach the next station is(1) 2 hour(2) 20 minute(3) 20 second(4) 40 minute
The distance-time graph of an object is a straight line parallel to the time axis, then the object is _(1) at rest(2) in uniform motion(3) moving with a uniform speed(4) moving with a non uniform speed
A car moves with a speed of $60 \mathrm{~km} \mathrm{~h}^{-1}$ for $20 \mathrm{~min}$ and then at a speed of $30 \mathrm{~km} \mathrm{~h}^{-1}$ for the next $20 \mathrm{~min}$. The total distance covered by the car is $\mathrm{km} .$(1) 10(2) 20(3) 30(4) 40
The distance-time graph of a body is as shown in the figure. The part of the graph that represents the uniform speed of the body is(1) $\mathrm{OA}$(2) $\mathrm{AB}$(3) $\mathrm{BC}$(4) Both OA and $B C$
A body moves with a uniform speed of $10 \mathrm{~km} \mathrm{~h}^{-1}$ for $2 \mathrm{~h}$. The average speed of the body is $\mathrm{km} \mathrm{h}^{-1}$(1) 10(2) 20(3) 5(4) 25
The distance-time graph of a moving vehicle is as shown in the figure.(1) The speed of the vehicle is increasing with time.(2) The speed of the vehicle is decreasing with time.(3) The final speed of the vehicle is zero.(4) Graph is not possible.
21. $1 \mathrm{~km} \mathrm{~h}^{-1}= $$\mathrm{m} \mathrm{s}^{-1}$(1) $\frac{50}{3}$(2) $\frac{5}{18}$(3) $\frac{18}{5}$(4) $\frac{5}{8}$
Choose the correct statement (s).(1) Speed and velocity both have same units.(2) If a body has a speed of $50 \mathrm{~m} \mathrm{~s}^{-1}$ in a straight line path, then its velocity is $180 \mathrm{~km} \mathrm{~h}^{-1}$(3) Speed of a vehicle is measured by a device called speedometer.(4) All the above
A person starts from a point $\mathrm{P}$ and travels along a path $\mathrm{PQR} \mathrm{P}$ as shown in the figure. Then speed of the person is $\mathrm{m} \mathrm{s}^{-1}$(1) $0.2$(2) 20(3) 12$\begin{array}{ll}\text { (4) } & 0.4\end{array}$
A simple pendulum was given to a physics student to determine its time period. Arrange the following steps in sequential order to determine its time period.(a) Calculate the radius of the bob ' $R$ ' by dividing the diameter by 2 .(b) Take a metre scale and measure the length of the string from the point of suspension to the lower tip of the bob $(\ell)$.(c) Place the bob over a meter scale and hold it in position with two wooden blocks or stiff cardboards. Measure the diameter (D) of the bob.(d) Now, the length of the pendulum ( $\ell$ ) is given by $\left(\ell_{1}-\mathrm{R}\right)$.(e) Consider the formula $\mathrm{T}=2 \pi . \sqrt{\frac{\ell}{g}}$ Calculate the time period of the simple pendulum.(1) abcde(2) edcba(3) bcade(4) deabc
A body covers $20 \mathrm{~m}$ in $2 \mathrm{~s}$ and another $20 \mathrm{~m}$ in next $4 \mathrm{~s}$. Arrange the following steps in sequential order to find the average velocity of the body.(a) Find the displacements of the body in first $2 \mathrm{~s}$ and next $4 \mathrm{~s}$ from the given data.(b) Find the total displacement of the body.(c) Find the total time taken by the body to complete the total displacement.(d) Use the formula, average velocity $=\frac{\text { Total displacement }}{\text { Total time taken }}$(1) abcd(2) adcb(3) dcba(4) dbca
Time period of the pendulum bob is(1) 9(2) 6(3) $4.5$(4) 3
The number of oscillations completed by the bob in one second is(1) $1 / 6$(2) $1 / 3$(3) $1 / 9$(4) 1
The amplituhde of oscillation of the pendulum bob is $\mathrm{cm} .$(1) 15(2) 5(3) $2.5$(4) $\quad 7.5$
From the given figure the number of oscillations performed by the bob at the end of $21 \mathrm{~s}$ is(1) 3(2) 4(3) 2(4) $\quad 31 / 2$
Match the entries given in column $A$ with the appropriate ones in column $\mathrm{B}$.
When can the speed and average speed of a vehicle be equal?
While determining the time period of a simple pendulum, why the time for 20 or more oscillations is found?
Define amplitude and frequency. Write their SI units.
Name the physical quantity that measures fastness or slowness of a moving object.
Two cars 'A' and 'B' move on a straight road for the same time. Car 'A' covers $80 \mathrm{~m}$ and car 'B' covers 100$\mathrm{m}$. Which one of the two is faster?
What are quartz clocks? Which one is more accurate, the clock using pendulum or the quartz clock?
If the speed of an object is known, how can we find the distance covered by it in a given time?
Name the different types of graphs used to represent motion of a body?
Give an example where translatory and rotatory motion occurs simultaneously.
Define rest and motion.
Define acceleration and state its SI unit.
What is a seconds pendulum? What is its approximate length?
Find the relationship between the time period of the pendulum and the length of the pendulum.
In a $100 \mathrm{~m}$ race, 'A' touches the finishing line in $10.5$ second and 'B' touches it in 11 second. Who is faster, 'A' or 'B'?
What is meant by average speed? How is it calculated?
Mention the different units of time and speed.
What is an odometer and a speedometer?
When do we say that a pendulum has completed one oscillation?
Give an example of a motion which is rotatory as well as periodic.
What is the difference between an oscillatory and a vibratory motion
A car travels a certain distance with $42 \mathrm{~km} \mathrm{~h}^{-1}$ for 20 minutes and the remaining distance at $60 \mathrm{~km} \mathrm{~h}^{-1}$ for 30 minutes. What is its average speed of the whole journey?
The distance-time graph of a car is as shown in the figure.
Is the car moving with constant speed? Find the speed of the car at the end of 2 hour and 6 hour respectively.
A lorry driver sees a old man crossing the road. Suddenly he applies brakes and stops the lorry within $30 \mathrm{~s}$. If the initial speed of the lorry is $108 \mathrm{~km} \mathrm{~h}^{-1}$, find its deceleration.
Give two examples for each of the motion along a straight line, circular motion and periodic motion.
Define day and year. How do watches and clocks measure time? Explain.
What are the different points one must keep in mind while choosing a suitable scale for drawing a graph? Discuss.
Define velocity and explain how it is different from speed.
Derive the relation between acceleration, change in velocity and time.
What are uniform speed and non-uniform speed? Explain, with suitable examples
"Slow and fast are relative". Explain it with examples.
"Rest and motion are relative" Explain.
Define different kinds of velocity. Give one example of each kind.
Explain how will you change the time period of a simple pendulum.
In a race, two athletes 'A' and 'B' reach the finishing point in 20 second and 22 second respectively.(a) What is the ratio of their speeds?(b) If both are allowed to run with their respective speeds for a given time, what is the ratio of the distance covered by them?
The odometer of a motorcycle shows a reading of $10,237 \mathrm{~km}$ at $8: 30$ a.m.At $9: 00 \mathrm{a} \cdot \mathrm{m}$, it shows a reading $10,267 \mathrm{~km} .$ What is the speed of the motorcycle in $\mathrm{km} \mathrm{h}^{-1}$ ?
A simple pendulum of length ' $\ell$ ' and time period ' $\mathrm{T}$ ' on earth is taken onto the surface of moon. How should the length of the simple pendulum be changed on the moon such that the time period is constant. (Take $\left.g_{e}=6 g_{i n}\right)$
The length of a seconds pendulum is double. What happens to the time period of the pendulum?
What is a simple pendulum? Explain the terms time period, mean position and extreme positions of a simple pendulum.
Describe the experimental method to determine the time period of a simple pendulum.
When pendulum 'A' completes 20 oscillations, pendulum 'B' completes 30 oscillations. What is the ratio of their time periods?
Explain in detail about the different kinds of motion.
Explain in detail about periodic motion and non-periodic motion.