x v o t \u00bdat 2 x \u00bdat 2 2 xa t 2 t 2 2 xa 2 t x a 77 1 A ball is dropped from a

# X v o t ½at 2 x ½at 2 2 xa t 2 t 2 2 xa 2 t x a 77

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x = v o t + ½at 2 x = ½at 2 2 x/a = t 2 t 2 = 2 x/a / 2 t x a
77 1. A ball is dropped from a very tall building. Find the ball’s position and velocity after 2 seconds.
78 White board problems WB13) A book falls off .75 meter tall desk. a) How long does it take to reach the ground? What Equation do we need?
79 A ball is thrown straight up in the air, find the acceleration and velocity at various points in its path. Gravity always causes an acceleration downward . v = 19.6 m/s, up a = 9.8 m/s 2 , down v = 19.6 m/s, down a = 9.8 m/s 2 , down v = 9.8 m/s, down a = 9.8 m/s 2 , down v = 0 m/s a = 9.8 m/s 2 , down v = 9.8 m/s, up a = 9.8 m/s 2 , down
80 Ex 11) A rock is dropped from rest from a tall building. How far has it traveled after 3 seconds? 0 m/s ___ 9.8 m/s 2 3 sec x = v o = v f = a = t = ? m
81 Ex 12) A ball thrown down from a 20 m tall building with a speed of 15 m/s. How fast is it moving when it hits the ground? (choosing up as positive) x = v o = v f = a = t = -20 m -15 m/s ? -9.8 m/s 2 ?
82 Ex13) A ball thrown upwards from a 20 m tall building with a speed of 15 m/s. How fast is it moving when it hits the ground? x = v o = v f = a = t = -20 m 15 m/s ? -10 m/s 2 ?
83 WB14) A ball is thrown with a velocity of 25 m/s straight up. (a)How much time does it take to reach the top of its path? x = v o = v f = a = t = ? 25 m/s 0 m/s at top - 10 m/s 2 ? v = v o + a t v - v o = a t 0 m/s – 25 m/s - 10 m/s 2 t = t = 2.5 s v f - v o a t = Solve the following problem completely:
84 (b) How high does the ball go? x = v o = v f = a = t = ? 25 m/s 0 m/s at top - 10 m/s 2 2.5 s x = v o t + ½at 2 x = (25 m/s)(2.5 s) + ½(-10 m/s 2 )(2.5 s) 2 x = (62.5 m) + (- 31.25 m) x = 31.25 m
85 White board problems WB15) A ball is dropped from a 45 meter tall building. a) How long does it take to reach the ground? b) how fast is it moving after 2 seconds? c) How fast is it moving when it hits the ground?
86 White board problems WB15) A ball is dropped from a 45 meter tall building. a) How long does it take to reach the ground? b) how fast is it moving after 2 seconds? c) How fast is it moving when it hits the ground? 15) a) 3 seconds b) 20 m/s c) 30 m/s
87 WB14) Hubble throws a bone straight up with a speed of 35 m/s a) For how much time is it in the air? b) What is its velocity after 3.5 seconds? c) What is its velocity after 4 seconds? d) What is its velocity after 5.3 seconds? e) How high does the bone go?
88 WB14) Hubble throws a ball straight up with a speed of 35 m/s a) For how much time is it in the air? b) What is its velocity after 3.5 seconds? c) What is its velocity after 4 seconds? d) What is its velocity after 5.3 seconds? e) How high does the banana go? 14) a) 7 seconds b) 0 m/s (at top) c) -5 m/s d) -18 m/s e) 61.25 m
89 WB15) A man stands on top of a tall building and throws a rock straight down at 15 m/s. It takes 4.5 seconds to hit the ground. a. How tall is the building? b. How fast is the rock traveling right before it hits the ground.
90 WB15) A man stands on top of a tall building and throws a rock straight down at 15 m/s. It takes 4.5 seconds to hit the ground.

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