It is through this contact (or normal) force on our feet that we are able to perceive the force of gravity as weight. However, because our feet are in physical contact with the ground, there is also a normal force pushing upwards on our feet (Figure 1A). This opposing force is termed normal force, which in contrast to gravity, is a contact force that acts upon objects that are physically associated with one another.įor example, when we are standing on the ground, the force of Earth’s gravity pulls our body towards the ground. In fact, we do not feel the force of gravity unless there is some opposing contact force to counteract it. As the name implies, a non-contact force is one that acts between two objects that are not in physical contact with one another, meaning that we need not be touching Earth for gravity to be acting upon us. This attractive force, more commonly known as gravity, is a non-contact force that acts on us from a distance. Our weight on Earth depends on our mass, which is how much matter we are made of, as well as the force of attraction between our mass and the mass of planet Earth. To prepare for our journey, we must first understand what the heck weightlessness actually is. Our dreams of floating in space are closer to becoming reality than ever before. Weightlessness may only be for astronauts, but with the help of private companies like SpaceX, Blue Origin, and Virgin Galactic, becoming astronauts may not be so far-fetched. So, is dreaming really as close as we’ll ever get to floating in space? Is the magical experience of weightlessness really limited to the tiny proportion of human beings who get to call themselves something-nauts (you know, astronauts, cosmonauts, taikonauts, spationauts)? Not so fast. The weight of our rear ends pressed firmly into our seats brings us crashing back to planet Earth, back to reality. We have seen footage of astronauts floating around the International Space Station playing Ping-Pong with balls of water and Pac-Man with strings of M&Ms.įor a moment, as we watch these astronauts thriving in an environment completely alien to us, we are able to imagine ourselves floating around with them.
When a body is thrown vertically upward,v=0.Weightlessness is something many of us have dreamed about since we were kids. When a body is dropped freely from height,u=0. When a body is thrown vertically upwards,its velocity decreases ,g =negative. When a body is falling vertically downwards ,its velocity increases ,g=positive. The value of g on the moon is about one-sixth of the value of g on the earth.Įquation of Motion for freely falling bodies The value of g is maximum on the surface of earth,it decreases on going above the surface of earth or on going inside the surface of the earth. G=7.3 m/ s 2 at an altitude of 1000 km above the surface of earth. G=9.8 m/ s 2 at an altitude of 200 km above the surface of earth. Since the radius of earth at the equator is maximum,the value of g is minimum at equator.Īs we go up from the surface of earth, the distance from center of earth increases and hence the value of g decreases. Since the radius of earth at the poles is minimum,the value of g is maximum at poles. The earth is not perfect sphere,so the value of its radius R is not the same at the places on its surface. The value of g is constant at a given place on the surface of earth. The value of g is not constant at all places on the surface of the earth. When a body is thrown vertically upwards, it undergoes retardation of 9.8 m/ s 2 When a body is dropped freely, it falls with an acceleration of 9.8 m/ s 2
When an object falls on the ground under the action of earth’s gravity,i ts velocity increases at rate of 9.8 m/ s 2.
#DEFINE FREEFALL IN PHYSICS FREE#
The acceleration of an object falling freely towards the earth does not depend on mass of object.During free fall,heavier as well as light objects accelerate at same rate.įor Ex:When a feather and coin are dropped from a roof, coin reaches the ground first and feather takes time.įeather has large surface area and therefore experiences more resistance from air.Thus its speed decreases and reaches later.Coin has small surface area and therefore experiences less resistance from air.Thus its speed increases and reaches faster.If there was no air then feather and coin reaches the ground at same time.
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