Post on 16-Jan-2016
Projectile MotionEssential Questions: What impacts have analyzing projectiles had on society? What affects the path of a projectile?
Projectile MotionA projectile is an object with horizontal motion upon which the only force acting is gravity.
Give examples of projectiles.
How has the study of projectiles been important?
All projectiles take a parabolic path.
Why do you think it is called this?
The shape of its path looks like a parabola.
Projectile motion is made up of two parts (or components):A horizontal (x) component and a vertical (y) component.
The path a projectile takes is called its trajectory.
The horizontal distance a projectile travels is called its range.
Horizontally Launched Projectiles
The x and y components act independently of each other.
A bullet is fired horizontally and another is dropped at the same time from
the same height. Which bullet hits the ground first? Neither. They hit at the same time.
• The initial speed in the x direction is the initial speed of the object.
• The initial speed in the y direction is zero.
• The horizontal speed of a projectile is constant.
• The vertical motion of a projectile follows the same rules as free fall.
Horizontal (x) Vertical (y)d = d = v = a = t = t = d = vt d = ½ a t2
Where did vi t go?
d = vi t + ½ a t2
vi is zero, it cancels out
A football is thrown horizontally with a speed of 20 m/s. It hits the ground 0.3 seconds later. What is the range of the ball? 6.0mFrom what height was the ball thrown?0.44m
A projectile is launched horizontally from a height of 3.0 m. The range of the projectile is 6.0 m. How long did it taketo land?0.78 sWhat was the initial speed of the projectile?7.7 m/s