When a body is dropped from a height H, it falls freely due to the force of gravity. This is according to the first law of motion which states that any body is in a state of rest or in a state of uniform motion until an external force acts on it. When one holds the body at a height H above the surface of the earth, he is exerting a force in the opposite direction to prevent it from falling. Then the body begins to fall under the natural force of gravity.
Is this a uniform motion or, in other words, does the body travel equal distances in equal time intervals? No, the motion is accelerated when the acceleration due to gravity is equal to 9.81 m/s * s. In other words, it will cover unequal distances in equal intervals of time as the body approaches the earth’s surface.
Let’s apply Newton’s second law of motion to the falling object. At any point the external force on the body is m*a. Here a is equal to the force of gravitational attraction and is therefore equal to g. So the downward attractive force is m*g.
Let us calculate the time it takes to reach the ground from height H.
The laws of motion are S = u * t *t + 0.5 * g *t * t — (1)
Here u is the initial speed and is equal to 0.
S is the distance traveled or is equal to H.
H = 0.5 * gram * t * to H = 4.9 t * t. This can also be derived using the law of conservation of energy. So at any point during free fall the potential energy is equal to the kinetic energy 0.5 * m * v * v = m * g * h. vo the velocity of the body after time t under an acceleration of g can be calculated as v = u + gt where u is the initial velocity. So when the body is dropped from a height h, the initial velocity is 0. So v = gt. Applying the law of conservation of energy it is 0.5*m*g*g*t*t=m*g*h. So yours is 0.5 * g * t * t. In fact, all equations of motion can be derived using the law of conservation of energy.
So the time it takes for a body to fall from a height of 49 meters is sqrt (10) seconds, to fall from a height of 100 meters is sqrt (20.4) or 4.51 seconds Comparatively, the time it takes for a human being to run 100 m is 10 seconds so one can imagine the extent of the natural force of gravity.
Using the same equation (1) it is possible to calculate the distance traveled by a body, that is, half a minute. In half a minute or 30 seconds a body will reach the earth’s surface from a height of 4410 meters or 4.4 km. It can also be seen that in 1 minute or 60 seconds a body can fall from a height of 17,640 meters or 17.64 kilometers. It can also be verified immediately that the body does not cover equal distances in equal time intervals.
Another interesting aspect of free fall is that the equations of motion are independent of mass. But the mass can affect the movement if there is resistance due to the wind and if the surface of the body is not smooth. This can cause upward drag and the movement may not be uniform for all masses. But without air resistance or in a vacuum, the motion will be as described above.
