While riding a bicycle,if we stop pedalling,why does the bicycle begin to slow down?

$A$ body of mass $500 \, g$ is at rest on a frictionless surface. Calculate the distance travelled by it in $10 \, s$ when acted upon by a force of $10^{-2} \, N$. (in $, m$)

What type of force is acting in the cases given above?

$(a)$ Two objects of masses $100\, g$ and $200\, g$ are moving along the same line and direction with velocities $2\, m s^{-1}$ and $1\, m s^{-1}$ respectively. They collide and after the collision,the first object moves at a velocity of $1.67\, m s^{-1}$. Determine the velocity of the second object.
$(b)$ If a man jumps out from a boat,the boat moves backwards. Why?

State the law of conservation of momentum. Derive it by using Newton's third law of motion.

The velocity versus time graph of a ball of mass $50 \, g$ rolling on a concrete floor is shown in the figure. Calculate the acceleration and the frictional force exerted by the floor on the ball.