Newton's second law of motion gives us a measure of

$A$ man throws a ball of mass $0.5\, kg$ vertically upward with a velocity of $25\, m s^{-1}$. Find:
$(a)$ The initial momentum of the ball.
$(b)$ The momentum of the ball at the halfway mark of the maximum height (given $g = 10\, m s^{-2}$).

$(a)$ State Newton's third law of motion and give two examples to illustrate the law.
$(b)$ Calculate the force required to produce:
$(i)$ an acceleration of $2.5 \, m s^{-2}$ in a body of $4 \, kg$.
$(ii)$ an acceleration of $3 \, m s^{-2}$ in a body of $10 \, kg$.

$A$ gun recoils after firing to conserve

$(a)$ Define force and state three possible effects of force on an object.
$(b)$ $A$ motorcycle is moving with a velocity of $90 \, km \, h^{-1}$ and it takes $5 \, s$ to stop after the brakes are applied. Calculate the force exerted by the brakes on the motorcycle if its mass along with the rider is $200 \, kg$.

According to Newton's third law,every force is accompanied by an equal and opposite force. How then can anything move?