Projectile Motion –
Zero Launch Angle
Bellwork
Notes – Zero Launch Angle
Finish Video Analysis Lab
Mastering Physics Assignment
Exit Pass
Bellwork
Question 4.2
You drop a package from a
plane flying at constant
speed in a straight line.
Without air resistance, the
package will:
Dropping a Package
a) quickly lag behind the plane while
falling
b) remain vertically under the plane
while falling
c) move ahead of the plane while
falling
d) not fall at all
Question 4.2
You drop a package from a
plane flying at constant
speed in a straight line.
Without air resistance, the
package will:
Dropping a Package
a) quickly lag behind the plane while
falling
b) remain vertically under the plane
while falling
c) move ahead of the plane while
falling
d) not fall at all
Both the plane and the package have the
same horizontal velocity at the moment of
release. They will maintain this velocity in
the x-direction, so they stay aligned.
Follow-up: what would happen if air resistance is present?
Zero Launch Angle
Launch angle: direction of initial velocity with respect to
horizontal
4-3 Zero Launch Angle
This is the trajectory of a projectile launched horizontally:
Zero Launch Angle
In this case, the initial velocity in the y-direction is zero. Here are
the equations of motion, with x0 = 0 and y0 = h:
Zero Launch Angle
In this case, the initial velocity in the y-direction is zero. Here are
the equations of motion, with x0 = 0 and y0 = h:
Use these equations to
develop an equation
for how the X and Y
positions are related
Zero Launch Angle
Eliminating t and solving for y as a function of x:
This has the form y = a + bx2, which is the equation of a
parabola.
The landing point can be found by setting y = 0 and solving
for x:
Take Out Video Analysis Handout
• Under “Analysis/Questions”
• Let’s work on #5 in Lab Groups
• Then we’ll work on #s 3 & 4
– Based on more general Projectile Motion concepts
• Finish last two questions and turn handout in
– Finish both Paradigm ( Actual Plots ) and Lab handouts
– Both will be graded
Mastering Physics Assignment
• Homework grade!!
• Chapter 4 (Start Now – Due by 2 AM 10/24)
– Pay attention to what is practice, extra credit, etc.
• Chapter 5 (Can Start Saturday – Due by 2 AM 10/31)
• 2% of the 100 is deducted for each day late
Question 4.5
Cannon on the Moon
For a cannon on Earth, the cannonball would follow path 2.
Instead, if the same cannon were on the Moon, where g =
1.6 m/s2, which path would the cannonball take in the same
situation?
a
b
c
d
Question 4.5
Cannon on the Moon
For a cannon on Earth, the cannonball would follow path 2.
Instead, if the same cannon were on the Moon, where g =
1.6 m/s2, which path would the cannonball take in the same
situation?
The ball will spend more
time in flight because
gMoon < gEarth. With more
time, it can travel farther
a
b
in the horizontal
direction.
Follow-up: which path would it take in outer space?
c
d