Home
The football has 2 velocities.
Which velocity is the football player matching.
Horizontal velocity.
The football and the football player
have a constant horizontal velocity.
St. Mary's Show Me The Physics
Ex) A projectile leaves ground at an angle
of 60.° and a speed of 100.m/s.
(a) Find the initial vertical
component of the object's velocity

Ex) A
projectile leaves ground at
an angle of 60.°
and a speed of
100. m/s.
(a) Find the
initial vertical component
of the object's velocity
Ө = 60.°
V_{i} = 100. m/s
V_{iy} = ?
V_{iy}
= V_{i}(sinӨ)
= (100. m/s)sin60.°
V_{iy} = 87. m/s up
(b) Find
the objects
maximum height.
V_{iy} = 87. m/s
a_{y} = 10 m/s^{2} (ascending)
d_{y} (max) =?
V_{fy} = 0 (at
max height)
V_{f}^{2} = V_{iy}^{2}
+ 2ad
0^{2} = (87. m/s)^{2}
+ 2(10. m/s^{2})d
0 = 7569 + 20.d_{y}
subtract 7569 from both sides
7569 = 20.(d_{y})
d_{y} = 378 m
Actually ......
d_{y} = 380 m
(2 sig. figs)
ex) A rock is thrown from a cliff with
initial speed of 40. m/s at an angle of 45.° below the horizontal.
(a) What is the vertical component of the
initial velocity?

a) What is the
vertical component
of the initial
velocity?
Ө = 45.°
V_{i} = 40. m/s
V_{iy} = ?
V_{iy} = VsinӨ
= (40. m/s)sin45.°
(b) If the
rock strikes ground in 1 sec what is height of cliff?
(b) If the
rock strikes ground in 1.0 sec what
is
height of cliff?
d_{y} = ?
(height)
a_{y} = + 10. m/s^{2}
t = 1.0 sec
V_{iy} = 28 m/s
(from before)
d_{y} = V_{iy}t + (˝)at^{2}
= 28.m/s(1sec)+˝(10. m/s^{2})(1.0sec)^{2}
28 m + 5.0 m
d_{y} = 33 m down
At Peak,
V_{x}
= ?
V_{x}
= 9.0 m/s
h
Total Time in Air?
1.84 sec
(twice peak)
actually 1.8
(2 sig. figs.)
What will the horizontal velocity of the baseball be
just before it hits the ground?
9 m/s, Vx is constant
Monkey and
Hunter
Don Ion
(offsite)
Flash
Physics
Don Ion
St.
Mary's U. Astronomy and Physics Dept.

Onsite

Projectile Motion Game
St. Mary's Physics
Intro to
Circular Motion
ŠTony Mangiacapre.,
 All Rights Reserved [Home]
Established 1995
Use any material on this site (w/ attribution)
