Name _ Free-fall Practice Problems 1) A stone is dropped from the top of a cliff. It is seen to hit the ground below after 3.50 3_ How high is the cliff? [60.0 m] took King Kong to fall straight down from the top of the Empire State 2 Calculate how long it _ , ,, ) ). What was his velocity just before \"landing 7 [3-81 S; 36-3 111/5] Building (380 m high 3) A car rolls gently (v0 = 0) of? a vertical cliff. How long does it take to reach a speed of 90 kin/hr? [2.6 s] a speed of 25 m/s. (a) How high does it go? 4) A foul ball is hit straight up into the air with how long does it take to go up and come back [31.9 m] (b) How long is it in the air, that is, down again? [5.1 s] 5) A ball is thrown vertically downward with a velocity of 15 m/s from the roof of a building that is 22 rn high. How long does it take to hit the ground below? How fast was it gomg when in hit? [1.08 s; 25.6 mfs] 6) A ball is thrown vertically upward with a velocity of 15 m/s from the roof of a building that is 22 m high. How long does it take to hit the ground below? How fast was it going when in hit? [4.14 s; 25.6 m/s] 7) A ball player catches a hall 3.3 s after throwing it vertically upward. With what speed did he throw it, and what height did it reach? [16.2 m/s; 13.3 m] 8) A coin is tossed vertically upward and reaches a maximum height of 0.90 m before it comes back down. With what velocity was it thrown, and how long was it in the air? [4.2 mfs; 0.86 s] 9) The best rebounders in basketball have a vertical leap (that is, the vertical movement of a fixed point on their body) of about 120 cm. ' (a) What is their initial \"launch\" speed off the ground? [4.85 m/s] (b) How long are they in the air? [0.99 s] 10)An arrow is shot straight up with an initial velocity of 50 m/s. (a) Find the time to reach the highest point. [5.1 s] (b) How high does the arrow go? [127.6 m] (c) Find the arrow's height when the velocity is 25 m/s. [95.7 m] 11)An arrow is shot vertically upward from the top edge of a 300 m cliff with a speed of 50 m/s and it just misses the ed - - - - cliff? [91.5 m/s] as on the way down. What 15 its speed when it hits the base of the D ext to the school building when he grabs his roof. (He's really sweet on her and this is how he th an initial upward velocity of 16.5 mfs. The he purse in ight? [245 s] ua student is standing n girlfriend's purse and throws it up onto the . shows his affection!) He throws the purse W1 12)A mischievous Pad roof is I 1.0 m high. How long was t 13)The acceleration due the gravity on the Moon is l/ a baseball on Earth to reach a maximum height of 20 on the Moon? [120 m] If you caught it when it came elapse between your throw and catch? [12.1 s] at, how high could you throw a baseball back down, how much time would Challenge Problems: One second later she tosses up another 14) A girl, standing still, tosses a ball vertically upwards. the second ball is tossed. With what ball at the same velocity. The halls collide 0.5 s after velocity were they tossed? [9.8 m/s] f of a building. On the way down it passes a 2 m high 15) A brick is drOpped 'orn the rec window and is observed to pass from the top to the bottom of the window in 0.25 s. (a) How fast was it moving when it passed the top of the window? [6.8 mls] (b) How far below the roof ofthe building is the top of the window? [2.3 m] 16) A rocket is launched vertically. 1t burns its fuel in 4.5 s. and while it is burning fuel it accelerates upward at a rate of 15.5 m/s2. What maximum height off the ground does the rocket reach? [405.1 m] What is its total ight time? [20.7 s] wn upward with a velocity of 9 mls upward from the top of a high cliff. At d ball is dropped from the same spot. The red ball is observed to hit the eeond before the blue ball. How high is the cliff? [128.7 m] 17) A blue ball is thro the same time, a re ground below exactly one s 18) A ball is dropped off a high cliff, and 2 5 later another ball is thrown vertically downward with an initial speed of30 m/s. How long will it take the second ball to overtake the first? [1.88 s]