Unit 2 Class Notes Honors Physics The Kinematics Equations (1D Equations of Motion)

Day 3 Throw-ups, Come-downs, Throw-downs

UP +, DOWN - a = -9.8 m/s 2 v 2 = 0 (at the top) v 1 = 20 m/s a = -9.8 m/s 2 v 2 = 0 m/s To solve for “t”, use the quadratic formula

UP +, DOWN - a = -9.8 m/s 2 v 2 = 0 (at the top) Two VERY important things to know about the case where you throw an object up and catch it at the same height.  t 12 =  t 23 v 3 =  v

#2 v 2 = 0 m/s a = -9.8 m/s 2  x = 30 m v 2 = 0 m/s a = -9.8 m/s 2 v  = m/s Due to the fact that the ball is thrown and caught at the same height … 1 2 3

#2 v 1 = m/sa = -9.8 m/s 2  x = -1 m To solve for “t”, use the quadratic formula Only positive times make physical sense

#3 A man launches a popcorn ball straight up into the air. It reaches its peak, and then begins to fall back to the ground. 4 seconds after it was released from the man’s hand, a bird catches the ball 20 ft above the ground. What was the velocity at which the ball left the man’s hand?  t = 4 sec a = ft/s 2  x = 20 ft

TONIGHTS HW Complete pg. 63, #’s 83, 86-88, 102 Complete “Throw-ups and Throw- downs Worksheet” from your note packet.