A Problem You drop your cell phone while in the bathroom in front of the mirror while the water is running in the sink below If you are 045 meters above the sink how long do you have before your cell phone is a ID: 570191
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Slide1
Station 1: Free Fall
[A] Problem: You drop your cell phone while in the bathroom in front of the mirror while the water is running in the sink below. If you are 0.45 meters above the sink, how long do you have before your cell phone is a
gonner
.
G: E:
U: S: S:
[B] What is the acceleration due to gravity for Earth always? Will it be for any other planet, for example planet Mars?Slide2
Station 1: Free Fall KEY
[A] Problem: You drop your cell phone while in the bathroom in front of the mirror while the water is running in the sink below. If you are 0.45 meters above the sink, how long do you have before your cell phone is a
gonner
.
G: y= 0.45m ; a= -9.8 m/s2 ; Vi=0m/s
U: t=?
E: y=
Vit
+ (1/2)(a)(t2)
t=√[(2y)/a]
S: t= √[(2*-0.45m)/(-9.8m/s2)]
S: t= 0.30s
[B] What is the acceleration due to gravity for Earth always? Will it be for any other planet, for example planet Mars?
Acceleration due to gravity is always -9.8m/s2. For any other planet acceleration will be different than planet Earth.Slide3
Station 2: Horizontal Projectile
[A] Problem: A ball is kicked horizontally at 8.0 m/s from a cliff 80m high. How far from the base of the cliff will the stone strike the ground?
[B] What is the only formula’s you use in the x-direction for horizontal projectiles?Slide4
Station 2: Horizontal Projectile
KEY
[A] Problem: A ball is kicked horizontally at 8.0 m/s from a cliff 80m high. How far from the base of the cliff will the stone strike the ground?
Part 1) solve for t in y-direction Part2) Solve for x
y=
Vit
+ ½at2
Solve for t first,
Vx
=x/t
t=
sqrt
(2y/a) x=
Vx
*t
t=
sqrt
( 2*-80m/ -9.8m/s2) x= (8.0 m/s)(4.04s)
t=4.04s x= 32m
[B] What is the only formula’s you use in the x-direction for horizontal projectiles?
Vx
=x/tSlide5
Station 3: Free Fall
Problem:
Wil
-E-Coyote drops a bowling ball off a cliff to try to catch the Roadrunner. The cliff is 132m high.
A. How long does it take the ball to fall to the ground?
B. What is its impact velocity?
C. How far does it fall in the first 3.0 seconds?
D. How fast is it going at the end of 3.0 seconds?
E. How long would it take the same ball to fall if the cliff was on the moon (g = 1.63 m/s
2
)?Slide6
Station 3: Free Fall
KEY
Problem:
Wil
-E-Coyote drops a bowling ball off a cliff to try to catch the Roadrunner. The cliff is 132m high.
A. How long does it take the ball to fall to the ground? (5.19s)
t=
sqrt
(2y/a)
t=
sqrt
[
(2*-132m)/(-9.8m/s2)]
t
=5.19s
B. What is its impact velocity? (50.9 m/s)
Vf
=Vi + at
Vf
= 0m/s + (-9.8 m/s2)(5.19s)
Vf
= -50.9 m/s
C. How far does it fall in the first 3.0 seconds? (44m)
Y=
Vit
+(1/2)at2
y=(1/2)at2
y=(1/2)(-9.8m/s2)(3s)2
y=-44.1.m
D. How fast is it going at the end of 3.0 seconds? (29 m/s)
Vf
=
Vi+at
Vf
= 0m/s
+ (-9.8m/s2
)(3s)
Vf
= -29m/s
E. How long would it take the same ball to fall if the cliff was on the moon (g = 1.63 m/s
2
)? (12.7s)
t=
sqrt
(2y/a)
t=
sqrt
[(2*-132m)/(-1.63m/s2)
t=12.7s
Given for all Problems: a=-9.8m/s2
; y=-132m ; Vi=0 m/sSlide7
Station 4: Horizontal Projectile
[A] A golfer drives her gold ball from the tee down the fairway in a high arcing shot. When the ball is at the highest point of its flight:
A) The velocity and acceleration are both zero
B) The x-velocity is zero and the y-velocity is zero
C) The x-velocity is non-zero, but the y-velocity is zero
D) The velocity is non-zero, but the acceleration is zero.
[B] Create a x and y table and list the variables for the following
problem:An
airplane is in level flight at a velocity of 138 m/s and at an altitude of 1500 meters when one of its wheels falls off. How long does it take the wheel to reach the ground? (**YOU ARE NOT SOLVING THIS PROBLEM, JUST state the Givens and Unknowns**)Slide8
Station 4: Horizontal Projectile
KEY
[A] A golfer drives her gold ball from the tee down the fairway in a high arcing shot. When the ball is at the highest point of its flight: (answer c)
A) The velocity and acceleration are both zero
B) The x-velocity is zero and the y-velocity is zero
C) The x-velocity is non-zero, but the y-velocity is zero
D) The velocity is non-zero, but the acceleration is zero.
[B] Create a x and y table and list the variables for the following problem: An airplane is in level flight at a velocity of 138 m/s and at an altitude of 1500 meters when one of its wheels falls off. How long does it take the wheel to reach the ground? (**YOU ARE NOT SOLVING THIS PROBLEM, JUST state the Givens and Unknowns**)
X-
Vx
= 138 m/s
t=?
Y- a= -9.8m/s2
Viy
= 0 m/s
t=?
y= 1500 mSlide9
Station 5: Free Fall
Problem: During a tornado in 2008 the Peachtree Plaza Westin Hotel in downtown Atlanta suffered damage. Suppose a piece of glass dropped near the top of the hotel falling 215 meters.
A. Ignoring air resistance, how long would it take the piece of glass to hit the ground? Slide10
Station 5: Free Fall KEY
Problem: During a tornado in 2008 the Peachtree Plaza Westin Hotel in downtown Atlanta suffered damage. Suppose a piece of glass dropped near the top of the hotel falling 215 meters.
A. Ignoring air resistance, how long would it take the piece of glass to hit the ground?
G: y=215m ; a= -9.8 m/s2 ; Vi= 0 m/s
U: t=?
E: y=
Vit
+ (1/2)at2
t=
sqrt
(2y/a)
S: t=
sqrt
[(2*-215m)/(-9.8m/s2)]
S: t=6.62sSlide11
Station 6: Horizontal Projectile
[A] Problem: A rifle with a muzzle velocity of 200 m/s is fired with its barrel held into place horizontally. The bullet strikes the ground 112 meters away. How high is the gun being held above the ground?Slide12
Station 6: Horizontal Projectile
KEY
Problem: A rifle with a muzzle velocity of 200 m/s is fired with its barrel held into place horizontally. The bullet strikes the ground 112 meters away. How high is the gun being held above the ground?
G/U:
Vx
= 200 m/s; x= 112m ; t=?
y=? a=-9.8 m/s2 Vi=0 m/s
E:
Vx
=x/t
y=
Vit
+ (1/2)at2
S: Solve for t in x direction first.
Vx
=x/t
t= x/
Vx
t= 112m / 200m/s
t= 0.56 m/s
Solve for y given solved t in x direction is same for y.
y=
Vit
+ (1/2)at2
y= (1/2)at2
y= (1/2)(-9.8 m/s2)(0.56s)2
y= 1.54mSlide13
Station 7: Free Fall
[A] A rock gradually rolls off a cliff and falls to the ground below. It takes the rock 7.23 seconds to hit the ground below the cliff. How high is the cliff?
[B] What is the initial velocity for an object in free fall? Explain your reasoning.Slide14
Station 7: Free Fall KEY
[A] A rock gradually rolls off a cliff and falls to the ground below. It takes the rock 7.23 seconds to hit the ground below the cliff. How high is the cliff?
G: t=7.23s; Vi=0m/s; a= -9.8m/s2
U: y=?
E: y=
Vit
+ (1/2)at2
S: y= (1/2)(-9.8 m/s2)(7.23s)2
S: y= 256.14m
[B] What is the initial velocity for an object in free fall? Explain your reasoning.
Vi=0m/s, because object leaves from the top where there is no movement in the object at t=0s.Slide15
Station 8: Projectiles at Angles
[A] A diver jumps UP off a pier at an angle of 25o with an initial velocity of 3.2 m/s. How far from the pier will the diver hit the water. (Assume the level of water is the same as the pier)Slide16
Station 8: Projectiles at Angles
KEY
[A] A diver jumps UP off a pier at an angle of 25o with an initial velocity of 3.2 m/s. How far from the pier will the diver hit the water. (Assume the level of water is the same as the pier)
Vx
=
VicosO
Vy
=
Visin
(O)
Vx
=(3.2m/s)(cos(25))
Vy
= 3.2m/s sin(25)
Vx
= 2.9 m/s
Vy
= 1.35 m/s
a= -9.8 m/s2
Vx
=x/t t=?
X=
Vxt
t=(
Vf
-Vi)/ a
X= (2.9m/s)(0.28s) t= (-1.35 m/s – 1.35 m/s) / (-9.8 m/s2)
X=0.80m
t= 0.28sSlide17
Station 9: What Equation Do I use?
[A] An object falls from a high building and hits the ground in 9.0 seconds. Ignoring air resistance, what is the distance that it fell? Slide18
Station 9: What Equation Do I use?
KEY
[A] An object falls from a high building and hits the ground in 9.0 seconds. Ignoring air resistance, what is the distance that it fell?
Y=
Vit
+ (1/2)at2Slide19
Station 10: What Equation do I use?
Problem: A physics book slides off a horizontal table top with a speed of 1.10 m/s. It strikes the floor in 0.350 s.
[A] Find: The height of the table above the floor.
[B]. The horizontal distance from the edge of the table to the point where the book strikes the floor.Slide20
Station 10: What Equation do I use?
Problem: A physics book slides off a horizontal table top with a speed of 1.10 m/s. It strikes the floor in 0.350 s.
[A] Find: The height of the table above the floor.
Y=
Vit
+ (1/2)at2
[B]. The horizontal distance from the edge of the table to the point where the book strikes the floor.
Vx
= x/t