#### Transcript of Roughneck Physics: Projectile Motion

**Projectile Motion**

Facts:

**Equations:**

Trajectory

objects that are thrown or launched into the air.

**Vectors:**

is important too

is important

The details:

Examples: balls, people, cars

Air resistance and gravity only forces acting on projectile

Horizontal and vertical components are independent of each other. They are used to describe the motion of the projectile

Neglecting air resistance: speed up equals speed down, time up=time down

The combination of an initial forward velocity and the downward

vertical force of gravity causes the ball to follow a curved path.

This curved path is called the trajectory

Projectile Motion takes place in 2-dimensions: horizontal and vertical

The horizontal component has a constant velocity

The vertical component has a constant acceleration

The curved path can be described as a parabola

Diagrams

Comparison of vertical and horizontal components

Horizontal component is constant

Vertical component changes

Notice the horizontal speed is constant, but vertical speed

is changing by examining the length of the arrows (vectors).

**Time is common to both

x dimension a = 0

y dimension a = -9.8

**Video Examples**

**MIT: Hunter and Monkey**

**Bullet Drop vs. Fired**

Vectors: have direction and magnitude

ex: velocity, acceleration, force

scalars: magnitude but no direction

ex: speed, volume, mass, time

symbol: arrow, length represents magnitude and direction

Vectors in same direction are added

Vectors opposite are subtracted

Ex: Airplane flying 100km/h with tailwind 20 km/h (add) = 120 km/h

airplane flying 100km/h into a headwind 20 km/h (subtract) = 80 km/h

Resultant: the result of combining two vectors, it is the diagonal

resultant

horizontal velocity

vertical velocity

When horizontal and vertical componens are at right angles to each other, USE

Pythagorean Theorem to find resultant

Vector analysis of horizontal and vertical components

Hollywood:

The villain in Despicable Me

Projectiles launched at angle

Include cosine (x) or sine (y) of the angle with the initial velocity

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