If the acceleration of a particle is constant in magnitude but not in direction,what type of path is followed by the particle?

$(a)$ What is acceleration? Write its $SI$ unit.
$(b)$ Draw velocity-time graphs for an object having:
$(i)$ Uniformly accelerated velocity.
$(ii)$ Uniformly retarded velocity.

Prove that if a body is thrown vertically upward,the time of ascent is equal to the time of descent.

$(a)$ Differentiate acceleration from velocity.
$(b)$ Can a body have acceleration without change in magnitude of velocity? Explain with an example.
$(c)$ $A$ motor boat starting from rest on a lake accelerates in a straight line at a constant rate of $3 \, m s^{-2}$ for $8 \, s$. How far does the boat travel during this time?

$A$ train is travelling at a speed of $90\, km\, h^{-1}$. Brakes are applied so as to produce a uniform acceleration of $-0.5\, m\, s^{-2}$. Find how far the train will go before it is brought to rest. (in $, m$)

$A$ motor car slows down from $72 \ km \ h^{-1}$ to $36 \ km \ h^{-1}$ over a distance of $25 \ m$. If the brakes are applied with the same force,calculate $(i)$ total time in which the car comes to rest,and $(ii)$ total distance travelled by it until it comes to rest.