Free Fall problems 1) King Kong carries Fay Wray up the 321 m tall Empire State

Question

Free Fall problems 1) King Kong carries Fay Wray up the 321 m tall Empire State Building. At the top of the skyscraper, Fay Wray's shoe falls from her foot. a) How long will it take the shoe to reach the ground? b) How fast will the shoe be moving when it hits the ground? 2) A baby blue jay sits in a tall tree awaiting the arrival of its dinner. As the mother lands on the nest, she drops a worm toward the hungry chick's mouth, but the worm misses and falls from the nest to the ground in 1.50 s. How high up is the nest? 3) Billy, a mountain goat, is rock climbing on his favorite slope one sunny spring morning when a rock comes hurtling toward him from a ledge 40.0 m above Billy ducks and avoids injury. a) How long does it take the rock to reach Billy? b) How fast is the rock traveling when it passes Billy? 4) In order to open the clam it catches, a seagull will drip the clam repeatedly onto a hard surface from high in the air until the shell cracks. If a seagull flies to a height of 25 m, how long will the clam take to fall? 5) A unique type of basketball is played on the planet Zarth. During the game a player flies above the basket and drops the ball in from a height of 10 m. If the ball takes 5.0 5 to fall, find the acceleration due to gravity on Zarth. Tougher problem. Remember, time up=time down. 6) How long is Tina, a ballerina, in the air when she leaps up with a speed of 1.8 m/s?

Explanation / Answer

(1) y=321m, u=0, a=g=9.81ms-2 , v =final velocity (unknown)

           (a) Using y = ut + (0.5) a t2

                 subtituting all values give t=8 s

           (b)   Using v = u + at

                  Subtituting all values give v = 79.31 ms-1

(2)      u=0, t=1.50s, a=g=9.8 ms-2

                  Using expression y = ut + (0.5) a t2

                  Substituting all values give y=11.025 m

(3)    y=40.0m, u=0, a=g=9.8ms-2, v=velocity with which rock is passing by Billy (unknown)

           (a) Using y = ut + (0.5) a t2

                 subtituting all values give t=2.85 s

           (b)   Using v = u + at

                  Subtituting all values give v = 28 ms-1

(4)     y=25m, u=0, a=g=9.8ms-2

         Using y = ut + (0.5) a t2

         Substituting all values gives t=2.25s

(5) y=10m, t=5.0s, u=0

         Using y = ut + (0.5) a t2

             Substituting all values gives a=0.8 ms-2

(6)   u=1.8ms-1, Let t be the time up

       Also, when leaping up, the acceleration will be -g that is -9.8ms-2

       when at the highest point v = 0

       Using expression v = u + a t

       Substituting all values we get t = 0.18 s

   Since time up = time down

   The total time for which Tine is in the air = 0.18 + 0.18 = 0.36s

Related Questions

Navigate

• Browse (All)
• Browse F
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.