Horizontal & Angular Launch

QOTD A circus clown is launched horizontally from a human cannon 20 m above the ground. 1) Once he is launched, what would his path of travel look like? 2) Before the cannon is set up, what kinds of questions should the site physicist ask and answer? 3) If another clown dropped at the same time the first clown was launched, who would hit first? (They drop from the same height)

practice Questions you may be asked about projectiles: How far did it go? How high was the initial launch position? How fast was it launched? How long was it in the air?

Horizontal Launch X-Direction: Velocity is constant – no acceleration when ignoring air resistance. V=d(x) t * Initial velocity determines horizontal displacement.

Horizontal Launch Y-Direction: Vi=0, as if dropped! Acceleration is constant = -9.81m/s 2 Height determines time in the air.

Sample problem A water balloon is thrown horizontally from a height of 1.5 m (height of a 15 year- old boy).The balloon goes 8 m forward (location of 10 year-old boy). What was the initial velocity of the balloon? 1. draw the picture & choose coordinates 2. define horizontal variables 3. define vertical variables 4. solve

Practice Problem People in the movies often jump from buildings into pools. If a person jumps from the 10th floor (30m) to a pool that is 5.0m away from the building, with what initial horizontal velocity must the person jump?

Practice Problem A Red Sox Player hits a baseball straight forward with a velocity of 40 m/s with respect to the ground. If the ball is hit 2.0 m above the ground how far does the ball go? (Ans: 25m)

Projectile “Particulars” Time depends on _________. Horizontal displacement depends on _____. Horizontal and vertical motion are _____of one another.

Launched at an angle: MSWBAT Resolve vectors into their components and apply the kinematic equations to solve problems involving projectile motion.

1. A car moves at 20 m/s for 5 s. How far did it go? m/sFind the x and y components of velocity 20 ° 3. Evaluate your comprehension of horizontal-launch problems on the scale. cannon ball!!

The Drop…the Demon Drop Problem The Throw-It-Up Problem…an arrow is shot into the air…

The Demon Drop plus moving forward at a constant velocity. The Throw-It-Up plus moving forward at a constant velocity.

Launched at an Angle-The Plan How can you figure out the displacement, velocity, and acceleration of a projectile at any point in time during its flight? (How do we solve these problems?) 1. Resolve vectors into components. 2. Set up X and Y chart. 3. List knowns in each direction (horizontal & vertical). 4. Solve for the unknown using time in common, if appropriate. 5. Smile-you’re a physics ROCKSTAR & You love this!

Initial Velocity & Projectiles Projectiles Launched Horizontally The initial vertical velocity is 0. The initial horizontal velocity is the initial velocity. Projectiles Launched At An Angle –Resolve the initial velocity into x and y components. –The initial vertical velocity is the y component. –The initial horizontal velocity is the x component.

Projectiles Launched At An Angle A zookeeper finds an escaped monkey hanging from a light pole. Aiming her tranquilizer gun at the monkey, she kneels 10.0 m from the light pole, which is 5.00 m high. The tip of her gun is 1.00 m above the ground. At the same moment that the monkey drops a banana, the zookeeper shoots. If the dart travels at 50.0 m/s, will the dart hit the monkey, the banana, or neither one?

Solution 1. Draw the picture 2. Resolve Vi into components 3. Fill in knowns for X & Y direction 4. Find d y for the dart 5. Find d y for the bananna

Angular Projectile Motion Problems Assume no frictional effects! A projectile is fired with a velocity of 196 m/s at an angle of 60.0 o with the horizontal. Calculate a)the vertical velocity and the horizontal velocity of the projectile. b)the time the projectile is in the air. c)the horizontal distance the projectile travels. d)the maximum height the projectile reaches.

Solution: Draw the picture Resolve Vi into components Fill in knowns for X & Y direction Identify unknowns Make a plan to solve & do it

Practice Problem 2. A projectile is fired at such an angle from the horizontal that the vertical component of its velocity is 49 m/s. The horizontal component of its velocity is 61 m/s. a)How long does the projectile remain in the air? b)What horizontal distance does it travel? c)What is the initial velocity of the projectile?

Practice Problem A projectile is fired at an angle of 53 o with the horizontal. The speed of the projectile is 2.00 x 10 2 m/s. Calculate a)the time the object remains in the air. b)The horizontal distance it travels.

Solution

Practice Problem While standing on an open bed of a truck moving at a constant velocity of 22 m/s, an archer sees a duck flying directly overhead. The archer shoots an arrow at the duck and misses. The arrow leaves the bow with a vertical velocity of 98 m/s. a)For what time interval does the arrow remain in the air? b)What horizontal distance does the arrow travel while it is in the air? c)Where does the arrow finally land?

Practice Problem A golf ball is hit at an angle of 45 o with the horizontal. If the initial velocity of the ball is 52 m/s, how far will it travel horizontally before striking the ground?

Solution

Exit Ticket: Evaluate your angular-launch comprehension on the scale…