In projectile motion, this video shows that both balls hit the ground at the same time. Why? because you substitute acceleration in the equation d=1/2 a x t(squared) with gravity which is 10m/s d= 1/2(10)x t(squared). Since there is no air resistance, then the weight of the balls don't matter and gravity is the only force acting on them, and therefore they hit the ground at the same time.

Newton's second Law

Newton's Second Law







When the man hits the bell thingy, its shows how force is directly proportional to acceleration. Newton's second law states that acceleration is directly proportional to force and indirectly proportional to mass. When the man pushes the two people on the swings, we can see that the larger man does not go very far on the swing. Therefore we can prove that mass is indirectly proportional to acceleration because the more mass you have, the less acceleration you have.