A kid kicks a soccer ball of mass 430g so that the ball moves on a flat rough ground at a velocity of 16m/s towards a stairway. The ball experiences a constant frictional force of 5N over a distance of 200cm. it then hits the stairway and collides elastically with the edge of stairway which forces the ball to project vertically.At what point is the ball considered a free fall. Write BEFORE OR AFTER hitting the stairway. Give the reason for your answer
The ball is considered a free fall after reaching it's max. ht.
To determine at what point the ball is considered to be in free fall, we need to understand the concept of free fall and the conditions that define it.
Free fall refers to the motion of an object under the influence of only gravity, with no other forces acting upon it. In free fall, the object accelerates due to the force of gravity alone and follows a parabolic trajectory.
In this scenario, before the ball hits the stairway, it experiences a constant frictional force of 5N over a distance of 200cm while moving on a flat rough ground. The presence of friction indicates that there is an external force acting on the ball, opposing its motion.
Since there is a force opposing the motion of the ball, it cannot be considered to be in free fall. Therefore, the ball is not in free fall before hitting the stairway.
However, after the ball collides elastically with the edge of the stairway and projects vertically, it no longer experiences any external forces (discounting air resistance, which we will assume to be negligible for simplicity). At this moment, only the force of gravity acts on the ball, causing it to accelerate downwards. Therefore, after hitting the stairway, the ball can be considered to be in free fall.
In conclusion, the ball is considered to be in free fall after hitting the stairway, as at that point, it experiences only the force of gravity and no other external forces.