Solving for the Velocity and Height in a Difficult Kinematics Problem

AI Thread Summary
The discussion focuses on solving a kinematics problem involving a ball thrown from a roof. Key points include determining the height from which the ball is thrown, the initial velocity, and the angle of projection. Participants suggest using kinematic equations to analyze the motion in both horizontal and vertical directions. Specifically, they recommend breaking down the final velocity into its components using trigonometric functions based on the given angle. The conversation emphasizes the importance of organizing known variables and applying appropriate equations to find the unknowns.
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Homework Statement


In the figure, a ball is thrown leftward from the left edge of the roof, at height h above the ground. The ball hits the ground 1.07 s. later, at distance d = 27.5 m from the building and at angle θ = 67° with the horizontal.

4-36.gif


(a) Find h

(b) What is the velocity at which the ball is thrown?
magnitude
angle ° relative to the horizontal

(c) Is that angle above or below the horizontal?


Homework Equations





The Attempt at a Solution



Ive been staring at this problem for a while now and am out of ideas any help would be greatly appreciated.
 
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Did you try making a list of Δt, Δ(x or y), Vi, Vf, and a for both the x and the y directions, then seeing if you can apply a kinematic equation to solve for unknown variables?

For instance Vfy =sin67(magnitude of Vf) and Vfx = cos67(magnitude of Vf), so if you could use kinematics in one direction to solve for the magnitude of Vf, you would then know the final velocity in the other direction as well.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
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