What is Projectile Motion Instructional Objectives Students will

What is Projectile Motion?

Instructional Objectives: • Students will be able to: – Define Projectile Motion – Distinguish between the different types of projectile motion – Apply the kinematic formulas to projectile motion and then use those formulas to solve 2 D motion problems and labs

Projectile Motion • Two-dimensional motion of an object – Vertical – Horizontal

Types of Projectile Motion • Horizontal – Motion of a ball rolling freely along a level surface – Horizontal velocity is ALWAYS constant • Vertical – Motion of a freely falling object – Force due to gravity – Vertical component of velocity changes with time • Parabolic – Path traced by an object accelerating only in the vertical direction while moving at constant horizontal velocity

Examples of Projectile Motion • Launching a Cannon ball

Equations • X- Component • Y- Component Note: g= 9. 8 m/s^2 • Vectors

Factors Affecting Projectile Motion • What two factors would affect projectile motion? – Angle – Initial velocity Initial Velocity Angle

Class Exercise An object is fired from the ground at 100 meters per second at an angle of 30 degrees with the horizontal üCalculate the horizontal and vertical components of the initial velocity üAfter 2. 0 seconds, how far has the object traveled in the horizontal direction? üHow high is the object at this point?

Solution • Part a • Part b • Part c

Sample problem • The Royal Gorge Bridge in • Givens: y Colorado rises 321 m above distance is -321 the Arkansas River. m; x distance is Suppose you kick a rock 45. 0 m; a is -9. 81 horizontally off the bridge. m/s^2 The magnitude of the rock’s horizontal displacement is • Find initial 45. 0 meters. Find the velocity? speed at which the rock was kicked.

Solution • Need x = vx (t) and y = ½ a (t 2) • Use the y = ½ a (t 2) formula to solve for time. • T = √ 2 y / a then substitute this into the first equation for t. • X = √ -9. 81 / 2 (-321) (45) = 5. 56 m/s

Sample problem • 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?

Applications Any Ideas?

LAB TIME!!!