![]() ![]() The value of g is 9,8m/s² however, in our examples we assume it 10 m/ s² for simple calculations. Now it’s time to formulize what we said above. Thus our velocity can be found by the formula We talked about the increase in speed which is equal to the amount of g in a second. V=g.t where g is gravitational acceleration and t is the time. Look at the given example below and try to understand what I tried to explain above.Įxample The boy drops the ball from a roof of the house which takes 3 seconds to hit the ground. Calculate the velocity before the ball crashes to the ground. We have learned how to find the velocity of the object at a given time. Now we will learn how to find the distance taken during the motion. I give some equations to calculate distance and other quantities. ![]() Galileo found an equation for distance from his experiments. Using this equation we can find the height of the house in given example above. Let’s found how height the ball has been dropped? We use 10 m/s ² for g. I think the formula now a little bit clearer in your mind. We will solve more problems related to this topic. Now, think that if I throw the ball straight upward with an initial velocity. When it stops and falls back to the ground? We answer these questions now. Picture shows the magnitudes of velocity at the bottom and at the top. As you can see the ball is thrown upward with an initial v velocity, at the top it’s velocity becomes zero and it changes it’s direction and starts to fall down which is free fall. ![]() Finally at the bottom before the crash it reaches its maximum speed which shown as V’. We have talked about the amount of increase in the velocity in free fall. It increases 9,8m/s in each second due to the gravitational acceleration. In this case, there is also g but the ball’s direction is upward so the sign of g is negative. Thus, our velocity decreases in 9,8m/s in each second until the velocity becomes zero. At the top, because of the zero velocity, the ball changes its direction and starts to free fall. Before solving problems I want to give the graphs of free fall motion.Īs you see in the graphs our velocity is linearly increases with an acceleration “g”, second graphs tells us that acceleration is constant at 9,8m/s², and finally third graphic is the representation of change in our position. At the beginning we have a positive displacement and as the time passes it decreases and finally becomes zero. Now we can solve problems using these graphs and explanations.Įxample John throws the ball straight upward and after 1 second it reaches its maximum height then it does free fall motion which takes 2 seconds. ![]() Calculate the maximum height and velocity of the ball before it crashes the ground. (g=10m/s²)Įxample An object does free fall motion. Calculate the velocity of the object after 3 seconds and before it hits the ground. Two examples given above try to show how to use free fall equations. We can find the velocity, distance and time from the given data. Now, I will give three more equations and finishes 1D Kinematics subject. The equations are įirst equation is used for finding the velocity of the object having initial velocity and acceleration. Second one is used for calculating the distance of the object having initial velocity and acceleration. Third and last equation is timeless velocity equation. ![]()
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