Two cars each of mass $1000 \ kg$ are moving in a straight line but in opposite directions. The velocity of each car is $5 \ m s^{-1}$ before the collision during which they stick together. What will be the velocity of the combined cars after collision (in $m s^{-1}$)?

Write answers to the following:
$(i)$ Mention the direction in which the force of friction acts on a moving body. State its units.
$(ii)$ Name the property of bodies (or objects) to resist a change in their state of rest or of motion. Name the quantity that is a measure of this property.
$(iii)$ Name the physical quantity whose unit is $kg\, m s^{-1}$. Define this quantity.

For a $2 \ kg$ mass,the $v-t$ graph is given. Find the force experienced by the mass in $OA$,$AB$,and $BC$.

An object experiences a net zero external unbalanced force. Is it possible for the object to be moving with a non-$zero$ velocity? If yes, state the conditions that must be placed on the magnitude and direction of velocity. If no, provide a reason.

Name the $CGS$ unit of force. How is it related to Newton?

If a body experiences a net zero unbalanced force, then the body: