1. Introduction to Physical Science Monday, Wednesday, Thursday Tom Burbine tomburbine@astro.umass.edu

2. How things fall Heavy and light objects fall at the same rate The heavy object does not fall faster (as long as there is no air resistance) g = G M (does not depend on mass of object) d 2

4. How does gravity work? Gravity distorts space-time

5. Projectile motion Horizontal and vertical components of velocity are independent of each other Combination of motion produces trajectory of projectile Horizontal component –Velocity in horizontal direction Vertical component –Acceleration due to gravity in vertical direction

7. Horizontal direction Velocity is constant No acceleration is acting on the projectile

8. Vertical direction Acceleration due to gravity affects the projectile

9. Vertical direction Velocity at beginning = 0 Velocity at end = gt Average velocity = ½ gt Distance travelled = average velocity x time Distance travelled = ½ gt * t d = ½ gt 2

10. A ball of mass 1.0 kg rolls off a 1.25 m high lab table at a velocity of 6.0 m/s. How far away from the base of the table does the ball hit?

11. Need to calculate how long it will take the ball to hit the floor. Then calculate how far the ball will travel from the table

12. A ball of mass 1.0 kg rolls off a 1.25 m high lab table at a velocity of 6.0 m/s. How far away from the base of the table does the ball hit? d = ½ gt 2 t 2 = 2d/g t = sqrt(2d/g) = sqrt(2*1.25/9.8) = 0.505 s v =d/t d = t*v = (6.0)(0.505) = 3.03 meters

13. Any Questions?