projectile motion. what is a projectile? projectile – an object that moves along a 2-d curved...

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Projectile Motion

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Page 1: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

Projectile Motion

Page 2: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

What is a Projectile?• Projectile

– an object that moves along a 2-D curved trajectory

- does not have any propulsion when in flight

Page 3: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight
Page 4: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

Yes Examples Non Examples

• Tennis ball• Football• Golf ball• Basketball• Javelin• Jumping out of a car• Cannon ball

• Plane• Rocket• Missile

Page 5: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

Projectile Motion Example # 1

Page 6: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

The ball is in free fall vertically and moves at constant speed horizontally!!!

Page 7: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

Conclusions about Projectile motion

1) The horizontal component of a projectile’s velocity is constant (no acceleration)

2) Projectile experiences constant downwards acceleration (gravity)

3) Horizontal and vertical motion of a projectile are independent of each other (except they have a common time)

Page 8: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight
Page 9: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

Projectile Motion Example # 2

Page 10: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

Important Variables

• Time – Δt• Velocity – vi, vf

• Height – Δdy

• Distance – ΔdX

• Acceleration – a• Launch Angle - θ

Page 11: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

Strategy to Solving Projectile Motion Problems

• Analyze horizontal motion and vertical motion independently–Separate the velocity vector into x-

and y- components• Remember: Time is common

between them• Use an x/y chart to list givens

Page 12: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

Horizontal motion:- Constant velocity (0

accel.) in the x direction- Equation : v = d/t

Page 13: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

Vertical motion:- Constant acceleration - 9.81

m/s2 [down]- Use the accel. equations we

derived

Page 14: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

Two Types of Problems: One Dimensional Problems (no horiz. Velocity)

Case 1: Object dropped from restCase 2: Object thrown directly upwards

Two Dimensional Problems:Case 3: Rolled over an edgeCase 4: Shot at an angle

Page 15: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

For Two Dimensional Problems:

Break the initial velocity into horizontal and vertical components (using the given angle and trigonometry)

vy

θ

vx

Page 16: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

Projectile Motion Example # 3

Page 17: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

Example Question 1A tennis ball is rolled off a counter at 8 m/s,

what will it’s position be after 3s?

Example Question 2A golfer strikes a golf ball on level ground. The

ball leaves the ground with an initial velocity of 42 m/s [32o above the horizontal].

a) What will the ball’s position be after 4 s?b) What will be the maximum height attained?

Page 18: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight

• Example # 3: A cannonball is fired with velocity of 50.0 m/s [30º above the horizontal]. It is shot at the level battle field which is located 20.0 m below.• a) Calculate the horizontal

displacement of the cannonball.• b) Calculate the impact velocity of the

cannonball

Page 19: Projectile Motion. What is a Projectile? Projectile – an object that moves along a 2-D curved trajectory - does not have any propulsion when in flight