A motor bike running at $90 \,km h ^{-1}$, is slowed down to $54 \,km h^{-1}$ by the application of brakes, over a distance of $40\, m$. If the brakes are applied with the same force, calculate $(i)$ total time in which bike comes to rest $(ii)$ total distance travelled by bike.
What do uou understand by the term acceleration ? When is it positive and when is it negative ?
Write true or false for the following statements
A quantity which can be completely specified by magnitude as well as direction is called a scalar quantity.
The $v-t$ graph of cars $A$ and $B$ which start from the same place and move along straight road in the same direction, is shown. Calculate
$(i)$ the acceleration of car $A$ between $0$ and $8\, s$.
$(ii)$ the acceleration of car $B$ between $2\, s$ and $4\, s$.
$(iii)$ the points of time at which both the cars have the same velocity.
$(iv)$ which of the two cars is ahead after $8\, s$ and by how much ?
Name a physical quantity that essentially changes as a body moves.