Finding magnitude of horizontal velocity

AI Thread Summary
The discussion focuses on calculating the horizontal and vertical velocities of a cannonball launched horizontally from a cliff at 45.0 m/s. The horizontal velocity remains constant at 45.0 m/s throughout the motion. For vertical velocity, the formula vy = -g*t is used, where g is 9.8 m/s². Participants attempt to apply kinematic equations to find vertical velocities at 1, 2, 3, and 4 seconds, but some confusion arises regarding the correct application of the formulas. The conversation emphasizes the importance of distinguishing between displacement and velocity in projectile motion calculations.
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Homework Statement



A cannonball is launched horizontally from the top of a tall cliff with a horizontal speed of 45.0 m/s. The trajectory of the ball is shown in the diagram at the right. Determine the magnitude of the horizontal velocity and the vertical velocities of the cannonball after each of the 1.0 second time intervals. Use -9.8 m/s/s to calculate the values.

find horizontal velocity for t=1 second, t=2 seconds, t=3 seconds, t=4 seconds

Homework Equations



kinematic equations

The Attempt at a Solution


i think i would use the equation d=vit+1/2at^2
so i'd do 1/2(9.8)(1)^2
so it would be 4.9?
 
Last edited:
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hello115897 said:

The Attempt at a Solution


i think i would use the equation d=vit+1/2at^2
so i'd do 1/2(9.8)(1)^2
so it would be -4.9?

It's minus because it is faced downward ---> vy=vy0t-(1/2)*g*t2
 
im still not getting the right answer...
 
hello115897 said:
im still not getting the right answer...
Ups, I'm so sorry. That was the formula for displacement-d. The formula for vertical velocity would be:
vy=-g*t.
 

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