2 velocities
b. Objects propelled horizontally
 have 2 velocities V_{x}, V_{y}  V_{x }is determined by thrower
 V_{x} constant (neglect fricition)
 V_{iy} = 0 (initial vert. vel.)
 V_{y} changed by ........
force of gravity
Ex) Object thrown horizontally a velocity of 4 m/s
Object dropped/Objects thrown horizontally
Same: a) a_{y } (+10 m/s^{2 }) b) vertical drop  d_{y} _{c) time in air} d)_{ }same_{ }V_{y}
Compare each sphere's: A) height above the ground, B) time in the air
Ex1) A rock is thrown horizontally from the top of a cliff @ 150 m/s. a) How long does it take the rock to fall 45 m vertically.
Ex1) A rock is thrown horizontally from the top of a cliff @ 150 m/s. a) How long does it take the rock to fall 45 m vertically.
∆d_{y} = V_{iy}t + 1/2a_{y}t^{2}
45 m = 0 + ˝(9.8 m/s^{2})t^{2}
45 m = 4.9t^{2}
9 = t^{2}
t = 3 seconds
A rock is thrown horizontally from the top of a cliff @ 150 m/s b) Find the rock's vertical velocity at 45 meters
V_{fy}^{2} = V_{iy}^{2 }+ 2ad
V_{fy}^{2} = 0^{2 }+ 2(+9.8 m/s^{2})45m V_{fy}^{2} = 19.6(45)
V_{fy }= 30 m/s
Only X Equation
d_{x}  Horizontal distance
ORIGINAL QUESTION Ex1) A rock is thrown horizontally from the top of a cliff @ 150m/s. How long does it take the rock to fall 45 m vertically
c) What was the rocks' horizontal displacement after 3.0 seconds?
Given
V_{x} = 150 m/s (Object thrown horizontally)
d_{x} = ? (A.K.A. Range)
t = 3.0 seconds
** d_{x} = V_{x}t **
d_{x} = 150 m/s(3.0 seconds)
= 450 m
ŠTony Mangiacapre.,  All Rights Reserved [Home]

