Projectile motion- Notes

Does throwing a ball horizontally affect how fast it takes a ball to reach the ground

Poll

What do you think?

• Yes

• No

NO!

Horizontal velocity does not affect vertical velocity! They are independent of each other!

If you were to drop one object and throw another horizontally, and throw another identical object horizontally, which will hit the ground first?

What is projectile Motion?

Definition

Projectile motion is the motion of an object due to gravity. It has a parabolic shape. Gravity is the ONLY force acting on the object.

Multiple Choice

What force is acting on an object that is thrown horizontally?

• Force of acceleration

• Throwing force

• Gravity

• Force Normal

What are some situations that involve projectile motion?

What goes up must come down!

a) At the instant the snowball reaches its maximum height the vertical velocity is 0. It was going up, then switches to going down
b) the SPEED is the same when the snowball is at the same height as the launch height. (remember: VERTICAL velocity is not the same

a) no veritical velocity
b) The same spped it had upon launch

In a snowball fight, two siblings are tossing snowballs at one another. If the sister launches a snowball at her brother, at what point does the snoball have....

Think about it

Projectile Motion pg 2....

Horizontal Variables

Δd_x- range, how far it travels horizontally
v_x- horizontal velocity (DOES NOT CHANGE!)
Δt- time (time transcends direction; us the same time for both horizontal and vertical!)

Vertical Variables

​Δd_y- height
Δt- time
a- acceleration (-10 m/s² on Earth)
V_iy-intial vertical velocity
v_{y-changes along the path}
v_fy-Final vertical volicity

Solving for the parabolic path

One more thing to note......

Max height- half way through the parabolic motion, when the object is it the highest point....

This means that at this point...
1/2 Δt (half of the time of the entire flight path has passed)
1/2 of the distance (on level ground) has been covered.