Physics Unit 6 2D Motion Key ideas

The vertical component is accelerated Free fall Gravity only

Horizontal component is constant

Projectiles experience a net downward force due to gravity

U6 Review #4 Need to find dx dy = ½ g t2 to find time to be 0.55s Now substitute into dx=vt Range is 2.74m Skip 4b

U6 Review #8 Only gravity is acting on the object- always! Velocity: Vy at top =0 Vx is always constant! Acceleration is always 10 m/s/s but acting down

U6 Review #9 Both spheres will be in the air the same amount of time but the 5 m/s sphere will land further away Remember the bullet fired vs bullet dropped? http://www.youtube.com/watch?v=D9wQVIEdKh8

#9 continued Also, remember that each sphere, or any object for that matter, is affected in the vertical direction with dy=1/2gt2. If both objects fall from the same height, regardless of horizontal velocity (even if it’s 0), they fall in the same amount of time from the same height. Range will be different because of dx=vt. Velocity in the horizontal is different, but since time is the same, the range, or dx, will be different.

U6 Review #10 and 11 http://www.physicsclassroom.com/Class/vectors/U3l2b.cfm In both situations remember how the horiz and vert velocity components change/don’t change Horiz is always constant and the object will always be positioned above/below the moving object (snowmobile/plane/truck/person, ect) #10- in the snowmobile #11 lands directly below plane

One more Fire a bullet horizontally and it hits the ground 1 second later. If you fire it twice the speed in the same direction, how long would it take to hit the ground? Think about the penny flick/mythbusters Similar situation to #9. Use the PhET simulator to help you understand this.