Flashcards in Projectile Motion Deck (14)

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1

## Projectile

### Object in free-fall that is affected only by gravity and air resistance

2

## Trajectory

### Flight path of a projectile

3

## Release

### When object becomes a projectile

4

## Apex

### Highest point of trajectory

5

## Primary Purposes in Projecting

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Maximize horizontal distance (javelin, discus, shotput, long jump)

Maximize vertical height (High jump, pole vault)

Maximize Accuracy (archery, golf)

Maximize Accuracy when speed enhances effectiveness (football pass, baseball throw, tennis shot)

Maximize time in the air (gymnastics, figure skating, diving)

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## Factors Influencing Projectile Motion

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1. Relative height of release (projectile height)

What height was projectile released?

What height did projectile land?

2. Angle of release (projection angle)

3. .Velocity of release (projectile velocity)

Magnitude of the velocity (= speed): how fast?

7

## Projectile Height

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Given a constant projectile velocity & angle:

↑ projectile height → ↑ flight time → ↑ horizontal displacement

3 ways projectile height influences projectile motion

8

## Projection Angle

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Influences shape of projectile’s trajectory

Projection θ = 90° → Vertical trajectory

vx = 0

Projection θ between 0-90° → Parabolic trajectory

Projection θ = 0° → latter ½ of parabolic trajectory

vy initial = 0

9

## Optimal Projection Angle?

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Depends on goals of performance

Maximize vertical displacement → steep projection θ

Exp: high jump, pole vault

Maximize horizontal displacement → small projection θ

Exp: long jump, triple jump

Depends on projection height

Release Ht = Landing Ht → Optimal projection θ = 45 °

Exp: kick a ball for max horizontal displacement

Release Ht > Landing Ht → Optimal projection θ < 45 °

Exp: throw a ball for max horizontal displacement

Release Ht < Landing Ht → Optimal projection θ > 45 °

Exp: throw a ball onto elevated surface

10

## Projectile Velocity

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Given a constant projectile angle & height:

Projectile velocity determines magnitude of vertical & horizontal displacement

velocity is a vector

velocity has a horizontal (vx)

and vertical (vy) component

11

## Projectile Vertical Component

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Vertical Component (vy)

Influences max vertical displacement (apex)

Constantly changing due to gravity

12

## Projectile Horizontal Component

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Horizontal Component (vx)

Influences horizontal displacement (range)

Remains constant (assuming minimal air resistance)

13

## Importance of Velocity, Angle, and Height of Release

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Projectile Velocity: most important

↑ vx → ↑ horizontal displacement (range)

↑ vy → ↑ time up & ↑ time down → ↑ total flight time

Projectile Height

↑ total flight time

↑ total flight time → ↑ horizontal displacement (range)

vx and vy remain same

Projectile Angle

Affects ratio of vx & vy

Minimal effect since ↑ in one are offset by ↓ in the other.

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