Ch+2+Sec+4+KirnumB

Section 4
toc What do you see? What do you think? The angle that it is thrown, gravity (other interrupting forces), and the force it was thrown with determine how far an object thrown into the air travels before landing.

Investigate 1) a. Yes, the same time 2) a. The coins hit the floor at the same time 3) a. No b. Yes, it moves faster c. 4) a. They do, it takes less time to get to the floor; if it is dropped from further up, it would travel farther because it has more time to do so. 5) a. The ball will go behind him 6) a. The ball takes the same amount of time it takes for the student to move to catch it; it moved in an arch like motion. Vertical component of velocity decreases on the way up and increases on the way down. The horizontal components of velocity do not change. b. Speed; trajectory is PATH, resultants all string together

Physics Talk

Projectiles and Trajectories
 * Projectile: an object traveling through the air or other medium
 * the only force is weight
 * ignore air resistance
 * Trajectory: path of projectile
 * either ground to ground or vertical
 * g-g are symmetrical around the highest point
 * x and y info are independent from each other
 * Free fall
 * the only force is weight but is only vertical motion
 * vertical positions of free fall and projectile are the same
 * Horizontal motion doesnt affect its downward motion
 * It is the same as when a something is dropped vertically from the same hight that have the same mass
 * Vertical velocity is constantly chagning
 * as it rises, a ball slows down
 * as it falls, a ball speeds up
 * The horizontal speed of the object will remain constant since no force acts on the ball horizontally

Checking Up
 * 1) Yes, they have the same distance to travel and air acceleration is the same
 * No, when it rises, it gets slower; when it falls, it gets faster my 10m/s every second.
 * 1) Its velocity is 0, its acceleration is -9.8

What do you think now? It depends on the hight that it was thrown and the speed of the object throwing it

Physics to Go 6. A projectile's horizontal motion has no effect on its vertical motion and vice versa. I know this is true because In the chair, Ross threw the ball while moving and was still able to catch the ball from where he threw it. 7. They will reach the ground at the same time. 11. The ball was just thrown at 11.49 m/s! It only took .5s to reach the batter who was 5.755 m awa at 11.49 m/s!!

Video [|Angular Trajectory]

What Do you think now?

The distance an object travels after it is thrown is related to the angle at which it is thrown