Posted by chris on Thursday, March 31, 2011 at 11:02pm.
an example of projectile motion would be the motion of the baseball when it is hit by the bat,, it the trajectory (the path followed by the object) has the shape like a parabola. projectile motion is possible because of gravity.
about the velocity, since it followed a path that looks like a parabola, it has x- and y-components, also because it's direction is directed at a certain angle, theta. the velocity at x-direction is constant and for an initial velocity, vo, the the velocity at x-dir is:
vo,x = vo (cos theta)
the displacement (or the range) is therefore given by:
R = (vo,x)*(t)
where t = time
for the y-component of velocity, it is not constant and it follows the formula for uniformly accelerated motion:
h = (vo,y)*(t) - (1/2)(g)(t^2)
where
vo,y = velocity at y-dir
h = change in height
t = time
g = acceleration due to gravity (9.8 m/s^2)
for the acceleration, since the path is not linear, the total acceleration has two components:
(i) the tangential acceleration which is tangent to the path (this is the change in SPEED)
(ii) the normal acceleration which is perpendicular to the tangential acceleration (this one determines the DIRECTION)
hope this helps~ :)