A small rock is thrown vertically upward with a speed of 13.0 m/s from the edge of the roof of a 20.0 m tall building. The rock doesn't hit the building on its way back down and lands in the street below. Air resistance can be neglected.

A.) What is the speed of the rock just before it hits the street?

B.) How much time elapses from when the rock is thrown until it hits the street?

  1. 👍 0
  2. 👎 0
  3. 👁 527
  1. a) consider energy
    Intial KE+ initailPE= finalKE
    1/2 m 13^3+ mg*20=1/2 m vf^2 solve for Vf.

    b) time?
    avg veloctity= (-13+vf )/2

    time= distance/avg velocity= 2*20/(Vf-13)

    1. 👍 0
    2. 👎 0
  2. A stone was thrown upward from the cornice of a tall building 50 m in height with an initial speed. It misses the cornice on its way down and strikes the ground 10 seconds after it was thrown. Find the initial speed.

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. science

    a ball is thrown straight upward and returns to the thrower's hand after 3.00s in the air. A second ball is thrown at an angle of 30.0 deg with the horizontal. At what speed must the second ball be thrown so that it reached the


    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

  3. Physics

    a small rock with mass 0.20 kg is released from rest at point A which is at the top edge of a large, hemispherical bowl with radius R = .5m. assume that the size of the rock is small compared to R, so that the rock can be treated

  4. Math

    A rock is thrown upward from a bridge that is 88 feet above a road. The rock reaches its maximum height above the road 0.67 seconds after it is thrown and contacts the road 3.18 seconds after it was thrown. Define a quadratic

  1. Math

    For this problem, a person standing on the edge of a cliff throws a rock directly upward. it is observed that 2 secs later the rock is at its maximum height (in feet) and that 5 secs after that (meaning 7 seconds after being

  2. pyshics

    A small rock moves in water, and the force exerted on it by the water is given by the equation Fd = kv, where k is a constant. The terminal speed of the rock is measured and found to be 2.0m/s. The rock is projected upward at an

  3. physics

    A rock is thrown vertically upward with a speed of 14.0 m/s from the roof of a building that is 50.0 m above the ground. Assume free fall. In how many seconds after being thrown does the rock strike the ground? in s What is the

  4. physics

    two students are on a balcony 20.6 m above the street. One student throws a ball vertically downward at 14.7 m/s. At the same instant, the other student throws a ball vertically upward at the same speed. The second ball just

  1. physics

    A man leans over the edge of a cliff and throws a rock upward at 4.9 m/s. Neglecting air resistance, two seconds later the rock's speed is what?

  2. Physics

    You throw a small rock straight up from the edge of a highway bridge that crosses a river. The rock passes you on its way down, 7.00 s after it was thrown. What is the speed of the rock just before it reaches the water 29.0 m

  3. Physics

    A rock is thrown vertically with a velocity of 21 m/s from the edge of a bridge 41 m above the river. How long does the rock stay in the air? V = 21 m/s d = 41 m a = -9.80 m/s^2 t = ?

  4. math

    A ball is thrown from the edge of a cliff with an initial velocity of 60·m/s upward. Answer the following questions using + (upward) and - (downward) to indicate the direction of the velocity. Ignore air resistance and assume the

You can view more similar questions or ask a new question.