Projectile Motion

by Judy Hutton

Projectile motion

Projectiles are objects that are thrown or launched into the air and are subject to gravity.​

Projectiles have motion in two dimensions

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Y=height and has accelerated motion, due to Gravity (9.8m/s²)

​

X= distance or "Range" is a constant motion.

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Resolving motion into its component vectors is easiest using trigonometry.

Objectives

• define projectile motion

• describe the properties of projectile motion

• solve problems involving projectile motion

Multiple Choice

What is the horizontal acceleration of a projectile?

• 0 m/s²

• 9.8 m/s²

• -9.8 m/s²

• 4.9 m/s²

Multiple Choice

If you throw a baseball straight up, what is its acceleration at the highest point?

• 9.8 m/s²

• 9.8 m/s

• 0 m/s²

• 0 m/s

Multiple Choice

If you throw a baseball straight up, what is its velocity at the highest point?

• 9.8 m/s²

• 9.8 m/s

• 0 m/s²

• 0 m/s

Multiple Choice

An object is projected horizontally from a cliff. The time it takes to hit the ground is

• more than if it was just dropped

• less than if it was just dropped

• the same amount of time than if it was just dropped

• impossible to determine

Multiple Choice

If I throw a crayon straight up at 12m/s, how fast is its speed when i catch it at the same height?

• 6 m/s

• 12 m/s

• 18 m/s

• 24 m/s

What is projectile motion?

• motion in two or three dimension

• motion through air or space, acted on only by gravity (and or air resistance, if any)

What are the components of projectile motion?

• along horizontal component, motion is uniform motion and there no acceleration along horizontal

• along vertical component, it is commonly known as the free fall, and it is acted upon by gravity only

projectile calculations

types of projectile motion

• projectile launched horizontally

• projectile launched at an angle

projectile launched horizontally

• the projectile travels the same horizontal distance in equal times between each flash

• 
  

projectile launched at an angle

projectile launched at an angle

especial case, launched on top at an angle

projectile motion kinematic equations

1. Find the time of flight of the cannonball.

2. What is the magnitude of velocity just before it strikes the ground?

An object is thrown horizontally.

1. Find the time of flight of the object.

2. How far from the edge of the cliff will the object be?

How will you describe the magnitude of velocities in vertical as it goes up approaching peak point and as it start to go down. How about the horizontal velocity?

Multiple Choice

As an object travels through the air, its vertical velocity 

• changes continuously
• remains the same

Multiple Choice

When a ball is projected horizontally, what is its initial vertical velocity?

• 10
• 0
• not enough information given

Multiple Choice

An object is shot from the ground (at 25 m/s) at 25 degrees and 65 degrees.  Which one rises to a higher height? (assume no air resistance)

• 25 degrees
• 65 degrees
• same for both

Multiple Choice

An object is shot from the ground (at 25 m/s) at 25 degrees and 65 degrees.  Which is in the air for longer? (assume no air resistance)

• 25 degrees
• 65 degrees
• same for both

Multiple Choice

If a bullet is horizontally shot at the same moment another bullet is dropped from the same height, which will hit the ground first?

• Shot Bullet
• Dropped Bullet
• Hit at Same Time

Multiple Choice

Two balls of the same mass begin at a height of 2m. One is released from rest while the other begins with a horizontal velocity of 5m/s. Which object its the ground first?

• Ball A
• Ball B
• Both balls his the ground at the same time
• unable to determine with information given

Multiple Choice

What force acts in the y direction that causes an object to travel in a parabolic arc?

• Friction
• Gravity
• Tension
• No force acting.

Multiple Choice

Two objects - one with mass m and the other with mass 2m - are released from rest at the same height. Which object hits the ground first?

• mass m
• mass 2m
• both objects hit the ground at the same time
• unable to determine with information given

Multiple Choice

Two objects of the same mass are launched from the ground. Object A has a launch angle of 45, while Object B has a launch angle of 65. Which object has the greatest maximum height height?

• A
• B
• Both objects reach the maximum height
• unable to determine with the given information

Multiple Choice

Two objects of the same mass are launched from the ground. Object A has a launch angle of 45, while Object B has a launch angle of 65. Which object will hit the ground first?

• A
• B
• Both objects hit the ground at the same time
• unable to determine with the given information

Multiple Choice

A projectile is launched from a height with an initial velocity v_0,x. The v_f,x represents the final horizontal velocity before impact.

• v_0,x = v_f,x
• v_0,x < v_f,x
• v_0,x > v_f,x
• unable to determine

Multiple Choice

In the diagram, which letter represents the horizontal displacement $$\overrightarrow{d}_x$$ ?

• A

• B

• C

• D

Multiple Choice

A ball rolls off a table and strikes the floor, as shown. If the time the ball spent in the air was 0.58 s, how fast did the ball leave the table?

• 3.6 m/s

• 1.2 m/s

• 2.9 m/s

• 0.99 m/s

Multiple Choice

A skateboarder rolls off a bridge into the river as shown. If the skateboarder was originally moving at 7.0 m/s, how much time did the skateboarder spend in the air?

• 1.3 s

• 0.79 s

• 38.5 s

• 0.70 s

• Not enough information given.

Multiple Choice

A skateboarder rolls off a bridge into the river as shown. If the skateboarder spent 0.79 s in the air, how far above the river is the edge of the bridge?

• 5.5 m

• 0.70 m

• 1.3 m

• 3.1 m

• Not enough information given.

Multiple Choice

In the picture, cannonball A was launched at 10 m/s at 60°, and B was launched at 18 m/s at 25°. The cannonball that hit the ground first was

• A, because it had less total velocity.

• B, because it had more total velocity.

• A, because it had less initial vertical velocity.

• B, because it had less initial vertical velocity.

Multiple Choice

A projectile is launched with a horizontal velocity of 20 m/s and an initial vertical velocity of 20 m/s. Which graph correctly shows the vertical velocity of the projectile over time?

Multiple Choice

A projectile is launched with a horizontal velocity of 20 m/s and an initial vertical velocity of 20 m/s. Which graph correctly shows the horizontal velocity of the projectile over time?

Multiple Choice

A projectile is launched, and its vertical and horizontal velocities are shown in the graph. What is the magnitude of the projectile's initial velocity?

• 25 m/s

• 10 m/s

• 325 m/s

• 18 m/s

Multiple Choice

A projectile is launched with a horizontal velocity of 20 m/s and an initial vertical velocity of 20 m/s. Which graph correctly shows the vertical position of the projectile over time?

Multiple Choice

A projectile is launched with a horizontal velocity of 20 m/s and an initial vertical velocity of 20 m/s. Which graph correctly shows the horizontal position of the projectile over time?

Multiple Choice

What is true about the vertical velocity of a projectile launched horizontally?

• It is initially at its maximum value.

• It increases due to gravity as it falls.

• It remains constant throughout its trajectory.

• It decreases as it falls due to gravity.

Multiple Choice

An airplane traveling at constant velocity drops a bomb. Where is the airplane when the bomb hits the

ground?

• above the bomb

• before the bomb

• past the bomb

Multiple Choice

The path followed by a projectile is also known as its

• trajectory

• range

• height

• vertical displacement

Multiple Choice

Once a projectile is launched, what is the only force that affects its motion?

• mass

• friction

• inertia

• gravity

Multiple Choice

Which of the following statements about the horizontal and vertical components of projectile motion is true?

• Changes in the horizontal component occur only when the vertical component changes.

• Both the horizontal and vertical components are always constant.

• The vertical component changes while the horizontal component stays the same.

• The horizontal and vertical components are dependent of each other.

Multiple Choice

Victor Velocity is standing on top of the roof of his house, firing stones with his slingshot over a level field. He is aiming straight outward, horizontally. If Victor pulls back harder on the sling to shoot a stone, which of the following quantities will be changed?

• The vertical displacement of the stone.

• The distance the stone travels, and the horizontal velocity.

• The time it takes the stone to strike the ground, and the horizontal velocity.