Projectile Motion: Time, Distance, and Velocity in 2D

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Homework Help Overview

The discussion revolves around a projectile motion problem involving a cannon ball fired horizontally from a height of 200.0m with an initial speed of 1000.0m/s. Participants are exploring the time it takes for the ball to land, its landing distance, and its velocity upon landing.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster expresses understanding of the first two parts of the problem but seeks clarification on how to approach the calculation of the velocity upon landing. Some participants suggest using constant acceleration formulas to find the vertical and horizontal components of velocity separately, while others mention the need to apply Pythagoras' theorem to determine the resultant velocity.

Discussion Status

Participants are actively discussing the methods to calculate the vertical velocity and are sharing insights on the use of kinematic equations. There is a recognition of the need to clarify the initial conditions and the application of formulas, but no consensus has been reached on the final approach to the problem.

Contextual Notes

Some participants note the initial vertical velocity is zero due to the horizontal launch, and the acceleration due to gravity is considered as -9.81 m/s². The discussion also highlights the use of specific kinematic equations, but the application of these equations remains a point of confusion for some.

blue__boy
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A cannon ball is fired horizontally at a speed of 1000.0m/s from a height of 200.0m

a.) How long does it take for the ball to land?
6.39s
b.) Where does it land?
6390m
c.) What is its velocity when it lands?



I get the a and b part...but i just don't understand what am i supposed to do with c.)

Thx for helping =]
 
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You can use constatnt acceleration formulae to calculate the y velocity and the x velocity as it lands separately.
Because the y and x axes are perpendicular to each other, you are able to use pythagoras' theorem to calculate the total velocity (the hypotenuse in this case).
 
oh...i am having trouble finding the vertical velocity too...
 
initial vertical velocity = 0ms-1, because it is only fired horizontally (no vertical components).
height = 200m
acceleration = -9.81ms-2

we can use the constant acceleration formulae: vf^2 = vi^2 + 2as --> Where s is displacement.
 

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