physics

a soccer player kicks a rock horizontally off a 40.0-m-high cliff into a pool of water. if the player hears the sound of the splash 3.00 s later, what was the initial speed given to the rock? assume the speed of sound in air to be 343m/s.

  1. 👍
  2. 👎
  3. 👁
  4. ℹ️
  5. 🚩
  1. Neglecting air friction, the time it will take the rock to hit the water is
    sqrt(2H/g) = 2.857 seconds. That means the sound of the splash takes 3 - 2.857 = 0.143 seconds to be heard, after hitting water. Sound travelled 49.05 m in that time. Since the cliff is 40 m high, the horizontal distance travelled by the rock was (from the Pythagorean theorem)
    sqrt[(49.05)^2 -(40)^2] = 28.4 m

    The rock's initial speed (and constant horizontal speed) was 28.4 m/2.857 s = 9.84 m/s

    1. 👍
    2. 👎
    3. ℹ️
    4. 🚩
  2. 9.84 m/s

    1. 👍
    2. 👎
    3. ℹ️
    4. 🚩

Respond to this Question

First Name

Your Response

Similar Questions

  1. Physics

    A person kicks a rock off a cliff horizontally with a speed of 20.0 m/s. It takes 7.0 seconds to hit the ground, find: a. height of the cliff b. final vertical velocity c. horizontal range

  2. Physics

    Find the magnitude of the impulse delivered to a soccer ball when a player kicks it with a force of 1350N. Assume that the player’s foot is in contact with the ball for 6.20x10-3s.

  3. PHYSICS HELP

    A 0.26-kg rock is thrown vertically upward from the top of a cliff that is 31 m high. When it hits the ground at the base of the cliff, the rock has a speed of 29 m/s . a.Assuming that air resistance can be ignored, find the

  4. Physics

    An astronaut is stranded on another planet with UNKNOWN GRAVITY. He conducts two experiments. In the first, he drops a rock from a cliff and he finds that it takes the rock 4.15 seconds to reach the ground at the base of the

  1. Physics

    A 3.0 kg rock is initially at rest at the top of a cliff. Assuming the rock falls into the sea at the foot of the cliff and that its kinetic energy is transferred entirely to the water, how high is the cliff if the temperature of

  2. Physics

    A soccer player kicks a rock horizontally off the a 40 m high cliff into the pool of water. if the player hears the sound of the splash 3 sec., what is the initial speed given to the rock? Assume the speed of the sound in air to

  3. physics

    Cliff divers at Acapulco jump into the sea from a cliff 37.1 m high. At the level of the sea, a rock sticks out a horizontal distance of13.39 m. The acceleration of gravity is 9.8 m/s^2. With what minimum horizontal velocity

  4. Physics

    A diver running 1.8 m/s dives out horizontally from the edge of the cliff and 3 s later he reaches the water below. (a) Calculate the resultant velocity (with direction) of the diver just before he hits the water. (10) (b) How

  1. Physics

    A boy kicks a rock off a cliff with a speed of 15.5m/s at an angle of 53.5° above the horizontal. The rock hits the ground 5.37s after it was kicked. How high is the cliff? I found the height of the cliff which is 7.45*10^1 m.

  2. college algebra

    A rock is thrown upward with a velocity of 28 meters per second from the top of a 38 meter high cliff, and it misses the cliff on the way back down. When will the rock be 7 meters from the water, below? Round your answer to two

  3. Physics

    A rock is thrown horizontally off of a cliff. It starts with a velocity of 4.2 m/s and the cliff is 68.2 m high. How long does the rock fall? I got 3.7 seconds but I do not know if it is right. (Help on these two) How far out from

  4. physics

    A person kicks a rock off a cliff horizontally with a speed of 20 m/s. It takes 7.0 seconds to hit the ground, find: a) height of the cliff b) final vertical velocity c) range

View more similar questions or ask a new question.