List two differences in tabular form between speed and velocity. When is a body said to have :
$(a)$ uniform velocity and $(b)$ variable velocity. How is the average velocity of a body is calculated when its velocity changes at a non$-$uniform rate ?
For difference see chapter at a glance.
$(a)$ If a body covers equal distances in equal intervals of time in a given direction.
$(b)$ When a body travels unequal distances in equal intervals of time or its direction changes or both change.
Average velocity will found out by finding the ratio (Net displacement$/$net time).
An aeroplane lands at $216\, km\, h ^{-1}$ and stops after covering a runway of $2\, km .$ Calculate the acceleration and the time, in which its comes to rest.
The following table show os the positon of three persons between $8.00\, am$ to $8.20\, am$.
Time | Position (in $km$) | ||
Person $A$ | Person $B$ | Person $C$ | |
$8.00 \,am$ | $0$ | $0$ | $0$ |
$8.05 \,am$ | $4$ | $5$ | $10$ |
$8.10\, am$ | $13$ | $10$ | $19$ |
$8.15 \,am$ | $20$ | $15$ | $24$ |
$8.20\, am$ | $25$ | $20$ | $27$ |
$(i)$ Who is moving with constant speed ?
$(ii)$ Who has travelled maximum distance between $8.00\, am$ to $8.05\, am$ ?
$(iii)$ Calculate the average speed of person $'A^{\prime}$ in $k m h^{-1}$
The velocity$-$time graph of a car is given below. The car weighs $1000\, kg$.
$(i)$ What is the distance travelled by the car in the first $2$ seconds ?
$(ii)$ What is the braking force at the end of $5$ seconds to bring the car to a stop within one second ?
Write any two equations of motion for a body having uniform acceleration.
Write true or false for the following statements
The motion in animals is called locomotion. Mechanics deals with the motion of non$-$living objects.