2. Projectile fired at an angle



Projectiles move
in a parabolic path

 

Baseball Throw- St. Mary's H.S. Physics



 

*** To understand this type of motion we must breakup the velocity into horizontal and vertical parts (components)

Angle & Components

Finding horizontal & vertical components (parts)

V - velocity of projectile fired

Vix - initial V in x direction

Viy - initial V in y direction

Use trig. to find Vix and Viy

Since…

COSq = A/H = Vix/V

CROSS MULTIPLY:

Then ..
Initial Horizontal component
of velocity

Vix = Vcosq
(on reference table)

 

 

Since…

 

sinq = Opp./Hyp. = Viy/V

 

CROSS MULTIPLY:

Then ..

Initial Vertical component of velocity

 

Viy = Vsinq
(on reference table)

 

 

Ex) A baseball is thrown at an angle of 30° and a velocity of 6 m/s. Find the initial horizontal and vertical velocity of the baseball.

 

Vertical Component

Viy = Vsinq

 

 

 

 

 = (6 m/s)sin30°

 

Viy = 3 m/s up


Horizontal Component

Vix = Vcosq

 

 

 = (6 m/s)cos30°

Vix = 5.2 m/s across

 

 

3. Other important facts

dx = Vxt 
(memorize)



ay =-9.8 m/s2
ascending (down -)

ay =+9.8 m/s2 descending
(down +)

Vy at peak = 0

 

 

Angles and Ranges

 

Projectile Range - Don Ion

 

 

 

0°, 90° - minimum range

45° produces maximum range

 

Horizontal and Vertical Velocity Components

 

 

Which angle of projection causes a projectile to stay in the air longer?  50 or 70 degrees

 

 

 

70 degrees, closer to 90, longer time in air