Projectile
an object that is propelled by a force initially, but when the force stops, it continues to move by virtue of its inertia
two forces that have to be present for the motion to be projectile:
force of gravity and air resistance
frizz bee is in the shape of and airplane wing. An airplane wing takes ___ of another force called ___ that helps it stay up.
advantage, lift
anything with an ___ is not a projectile motion
engine
Parabola
path travled by a projectile, curved
Goal of projectile motion:
to understand the parabolic path
Strategy to understan projectile motion:
-break motion into perpendicular components (horizontal, vertical)
-analyze the components of motion separately
-once you understand them separately put components back together
Rule of projectile motion:
mutually perpendicular components of motion are independent of each other
Rules of projectiles we are doing in class:
-no air resistance
only force present ----gravity (pushes downwards)
no forces acting horizontally----horizontal acceleration is 0
horizontal velocity----constant
ax-----0
ay-----g 9.8 m/s/s
Vx-----constant
Vy-----changing
When you fire/launch a horizontally launched projectile, its making a ___ angle with x axis
0?
Time of flight
determined by vertical motion t= vy-voy/g
Range
determined by horizontal motion x=vx . t
Max height
determined by vertical motion y= (Vyo + Vy/2) . t
Projectiles launched diagonally
two projectiles launched at the same speed, but at complementary angles of projection have the same range (they have the same horizontal distance)
the angle that gives you the biggest range for any given speed is ____
45?
the cosine of 60?= the sine of
30?
why do 30? and 60? have the same range?
they travel the same horizontal distance. The two equations for each angle balance out because the velocities trade places. Vx of graph A= Vy of graph B. Vy of graph A= Vx of graph B. 30?would have a big initial velocity, and a small time. 60? would have
Diagonal projectiles
projectiles launched diagonally at and angle that is not 0?
Diagonal projectiles rule:
any distance is found the same distance below the straight-line path, it would have taken in the absolute of gravity as any object falls in the same amount of time in free fall.
Magic numbers for acceleration in free-fall at each second
5, 20, 45, 80...
Vertical motion of a diagonally launched projectile determines...
the time of flight
Vy of a diagonally launched projectile represents
time