$(a)$ Write differences between speed and velocity.
$(b)$ The speed of a moving object is $x m s ^{-1}$. Its velocity is $y m s ^{-1}$. What is the similarity observed ?
Define acceleration. State a relationship connecting $u, v, a$ and $t$ for an accelerated motion. Give an example of a motion in which acceleration is uniform.
A piece of stone is thrown vertically upwards. It reaches its maximum height in $3$ second. If the acceleration of the stone be $9.8\, m s ^{-2}$ directed towards the ground, calculate the initial velocity of the stone with which it is thrown upwards. Find the maximum height attained by it.
Give one example for each of the type of motion when
$(i)$ acceleration is in the direction of motion.
$(ii)$ acceleration is against the direction of motion.
$(iii)$ acceleration is uniform.
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 ?