Ball Rise Trajectory: How Fast Was the Ball Moving?

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Homework Help Overview

The problem involves analyzing the trajectory of a tennis ball hit by a player, specifically determining the initial speed required for the ball to clear a net while traveling a horizontal distance of 12.6 meters at an angle of 3 degrees above the horizontal. The ball must rise at least 0.33 meters to clear the net.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants discuss different equations to relate the horizontal and vertical motions of the ball. Some suggest using the Pythagorean theorem to find the initial velocity, while others propose setting up separate equations for horizontal and vertical motion to solve for the initial speed.

Discussion Status

There are multiple approaches being explored, with participants questioning the assumptions about the time of flight and the relationship between horizontal and vertical components of motion. Some guidance has been offered regarding the setup of equations, but no consensus has been reached on a specific method or solution.

Contextual Notes

Participants note the lack of specified time in the problem, leading to different interpretations of how to approach the calculations. The discussion reflects uncertainty about the relationship between the components of motion and the necessary conditions to clear the net.

UrbanXrisis
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A tennis player standing 12.6 m from the net hits the ball at 3 degrees above the hoizontal. To clear the net, the ball must rise at lease 0.33m. If the ball just clears the net at the apex of its trajectory, how fast was the ball moving when it left the racket?

would it just be sqrt(12.6^2+0.33^2) ?
 
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no. find an equation relating the horizontal motion of the ball, to reach the net. find another equation relating the vertical motion of the ball to clear the net. solve the equations for v.
 
they do not specify time so I could have 12.6m/s ins the x direction and .33m/s in the y direction

hence:
v=sqrt(12.6^2+0.33^2)
 
Origin : the player's position.
Horizontal motion :
s=ut
12.6=(vcos3)*t
Vertical motion :
[tex]0.33=t*vsin3-\frac{g}{2}t^2[/tex]
Solve the equations for v.
 

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