Evans SPH 3U1
Physics Grade
11
Unit 1: Kinematics
Note 7: Projectile Motion
Reference: Chapter 2.3
Parabolic and Projectile
Motion:
Demonstrate Timing - If a ball is
thrown horizontally, it will stay in the air for exactly the same length of time
as a ball dropped from the same height no matter how fast you throw it.
Discuss pg. 84 #1-3
Demo car with popping ball
Projectile Motion – In projectile motion an object
really has 2 motions taking place simultaneously. These motions can be treated
separately. The only thing that these motions have in common is that they occur
in the same time interval. For ideal projectile motion conditions (absence of a
resisting force), the vertical motion is uniformly accelerated motion ( i.e.
free fall). The horizontal motion is simply uniform motion.
Solving projectile motion problems:
- Use equation
- Use component method of adding vectors.
- May need to use quadratic formula or factoring to solve
for time.
- Substitute time back in to find horizontal distance
travelled (horizontal range).
Example 1:
An object traveling at 3.0 m/s [forward] along a flat
friction reduced table top rolls off the table. Assume that the height of the
table is 4.0m. Calculate:
a)
the time of flight (Answer: 0.9s)
b)
the horizontal displacement of the object (Answer 2.7m [forward])
c) the impact velocity
Example 2:
A cannon is set at an angle of 45 degrees above the
horizontal. A cannonball leaves the muzzle with a speed of 2.2 x 102
m/s. Determine the cannonball’s:
a) time of flight (Answer: 32 s)
b) maximum height (Answer:
1.2 x 103 m )
c) horizontal range
(Answer: 4.9 x 103 m)
d) impact velocity
Example 3:
A cannon is set at an angle of 45 degrees above the
horizontal. A cannonball leaves the muzzle with a speed of 2.6 x 102
m/s. The cannonball lands on a hill that is 20. m high. Determine the cannonball’s:
a) time of flight
b) horizontal range
c) maximum height reached
d) impact velocity
Pg 81 #1,2 (Practice questions)
Pg 81 #1-8