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2D Motion Homework Solutions

2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

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Page 1: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

2­D MotionHomework Solutions

Page 2: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y
Page 3: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

ANSWERS:1. The Wooley Bear2.

3. 26.8 sec4. 12. 4 sec 

Vwest = .235 m/sVNorth = .348 m/s

Page 4: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

MMMMM Dinner!

Page 5: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

.42 m/s

34o

N

S

EW

Page 6: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

1.4 cm/s

*Done by applying trig to distances given.

Trig...

Kinematics...

Page 7: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

1.4 cm/s1.1 cm/s

*Done by applying trig to velocity vector.

Trig...

Kinematics...

*note it's the same answer and the same amount of work using either method.

Page 8: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

Conversion:

Given

1.59 cm/s2

2.4 cm

/s2

Trig applied to acceleration vector:

4ft = 121.9 cm ay = asinθ = (2.4 cm/s2)sin41o =1.59 cm/s2

*Note: Like #3, there are two ways to solve this one.You can apply trig to the distance information given or to the acceleration vector. 

Page 9: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

Mo4 Motion Deluxe#1  Can the x‐component of a vector be greater than the magnitude of the vector? 

How about the y‐component? Explain...

θ

V

Vx

Vy

#2 A golf ball is hit with an initial speed of 35 m/s at an angle less than 45o above the horizontal. 

  The horizontal velocity component is... 

(a) greater than , (b) equal to, (c) less than the vertical velocity component. Why?

35 m/s

#3  If the ball is hit at an angle of 37o, what are the initial horizontal  and vertical velocity components?

#4 The x‐ and y‐components of an acceleration vector are 3.0 m/s2 and 4.0 m/s2, respectively. The magnitude of the acceleration vector is...

#5  What are the magnitude and direction of the "resultant" acceleration vector shown in #4?

3 m/s2

4 m/s

2 a

θ

(a) less than 3.0 m/s2 

(b) betwen 3.0 m/s2 and 4.0 m/s2

(c) between 4.0 m/s2 and 7.0 m/s2

(d) equal to 7.0 m/s2

#6 If the magnitude of a velocity vector is 7.0 m/s and the x‐component is 3.0 m/s, what is the y‐component?

3 m/s

? m/s

7 m/s

θ

#7 The x‐component of a velocity vector that has an angle of 37o to the x‐axis has a magnitude of 4.8 m/s.

(a) What is the magnitude of the velocity?(b) What is the magnitude of the y‐component of the velocity?

4.8 m/s

? m/s

? m/s

37o

θ = 37o

Vx= (35m/s)cos37o = 28 m/s

Vy = (35m/s)sin37o = 21 m/s

Vx

Vy35 m

/s

a2 + b2 = c2... PYTHAGORIZE IT!

PYTHAGORIZE IT!

Use any trig function to get θ.... 

tanθ = (4/3)

θ = tan­1(4/3) = 53o

a) V = 6 m/s

b) Vy = 3.6 m/s

Page 10: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

  

P.M.P.M.D.D.Processed Meat Projectile Motion Demo Deluxe µs Timer

P.M.P.M.D.D.

PhotoGate

VerticalHorizontal

Tools

Tool

GivensGivens

SPAM

Page 11: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

2­D Mo Intro1.

VerticalHorizontal

Tools

Tool

GivensGivens

Answer = 733 m

http://www.potatorock.com/

Page 12: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

2.

VerticalHorizontal

Tools

Tool

GivensGivens

Answer = 2.3 m

Page 13: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

3.

VerticalHorizontal

Tools

Tool

GivensGivens

Answer = ­1.6 m/s2

Page 14: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

Team Name #1 #2 #3 #4 #5 #6 #7 #8

The It's 

All Ball

­

Bearing

s Nowad

ays

2­D Kin

ematics 

Relay De

luxeThe

 It's All 

Ball­

Bearing

s Nowad

ays

2­D Kin

ematics 

Relay De

luxe

Touch and DragThe Ball­Bearing 

Page 15: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

VerticalHorizontal

Tools

Tool

GivensGivens

#1

* No horizontal calculation needed.

Page 16: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

VerticalHorizontal

Tools

Tool

GivensGivens

#2*Find both Δx and Δy.

Page 17: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

VerticalHorizontal

Tools

Tool

GivensGivens

#3

* No horizontal calculation needed.

Page 18: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

VerticalHorizontal

Tools

Tool

GivensGivens

#4*Note: Its the same cliff fromproblem #3 so Δt = 1.59 sec

Page 19: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

VerticalHorizontal

Tools

Tool

GivensGivens

#5* Find Δt using vertical clues,then sub into horizontal.

Page 20: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

#6Vx = 3 m/s

Vy = ­ 4 m/s V =?θ =?

Page 21: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

VerticalHorizontal

Tools

Tool

GivensGivens

#7* Find Δt using horizontal clues,then sub into vertical.

Page 22: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

VerticalHorizontal

Tools

Tool

GivensGivens

#8 Vx = 6 m/s

Vy = ?

V = ?

θ = ?

*Find Vy using the vertical kinematics clues, then do trig on the vectors.

Vx = 6 m/s

Vy = ­68.6 m/s

V = ?

θ = ?

*any of these work

Page 23: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

Vx

Vx

Vx

Vx

Vy

Vy

Vy

Vy

V

V

V

V

VxVxVx

Page 24: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y
Page 25: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y
Page 26: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

Vx

.4 m

*Note that this is the same scenario as the Flick the ant problem from

Mo Mo Mo Motion worksheet, or the Bas A$$ bonus problem on Mo4.

Page 27: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

*This can be seen in the saw problem on Mo Mo Mo Motion worksheet.

Page 28: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

VerticalHorizontal

Tools

Tool

GivensGivens

*note that this one is the same exact scenario as problem #7 from the relay race.

Page 29: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

Aww come on guys....maybe you need a refresher course.

Page 30: 2D Motion - Hudson City School District€¦ · #3 If the ball is hit at an angle of 37o, what are the initial horizontal and vertical velocity components? #4The x‐ and y

100 m/s

Vyfinal