Kinematics


   
 
Maximum Height
 
Maximum height is denoted by the letter hmax or H. It is also known as the vertical range. It is the maximum height to which a projectile rises above the horizontal plane of projection. In order to calculate the maximum height H, we make use of the fact that the velocity vy(t) of the projectile at the maximum height is zero. If t is the time taken by the projectile to reach maximum height, then from the equation  vy = v sin q - gt
 
We have
 
 
At time t1, y (t) = H, the maximum height
 
 
Substituting for t1,
 
 
Time of flight
It is the total time taken by the projectile to return to the same level from where it was thrown.
 
Since the time of ascent is equal to the time of descent, the time of flight is equal to twice the time taken by the projectile to reach the maximum height.
 
Therefore, time of flight, T = 2t where t is the time of ascent or time taken by the projectile to reach the maximum height. Once again,
 
 
In the equation,
 
 
We have,
 
 
 
Hence, the time of flight, T = 2t
 
 
Horizontal range
 
It is the total horizontal distance from the point of projection to the point where the projectile returns back to the plane of projection. It is denoted by R.
 
To calculate the horizontal range, we need to consider the horizontal motion of the uniform velocity vcosq, in the horizontal direction. Hence, the horizontal range is given by,
 
 
 
 
 
 
Note: R = R maximum, when
 
 
Two angles of projection for the same range
Horizontal range is give by
 
 
 
 
 
 
 
This shows that there are two angles of projection for the same horizontal range i.e.,  J and (90o - J) with the horizontal. The projectile will cover the same horizontal range whether it is thrown at an angle (900-q) with the horizontal, or an angle q with the vertical.
 
 
     
   
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Kinematics