Ball thrown down simplify for time. HELP

AI Thread Summary
A student throws a ball downward at 8.0 m/s from a height of 25 m and needs to determine the time until it hits the ground and its impact velocity. The initial calculation using the formula d = ViT + 1/2aT^2 yielded an incorrect time of 3.4 seconds instead of the correct 1.6 seconds. Participants suggest re-evaluating the equation to x = Vi*t + 1/2*g*t^2 and using the quadratic formula to solve for time. The discussion emphasizes the importance of correctly applying the quadratic formula to find the accurate time of descent. Understanding these equations is crucial for solving similar physics problems effectively.
reltz
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Homework Statement


A student throws a ball downward at a velocity of 8.0m/s from a height of 25m. How long until it hits the ground? What is the velocity of the ball as it hits the ground.


Homework Equations


What is thee formula when simplifying for T(time)?


The Attempt at a Solution


When using the formula d=ViT + 1/2a*d I get 3.4s, but the answer is 1.6s.
 
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reltz said:

Homework Statement


A student throws a ball downward at a velocity of 8.0m/s from a height of 25m. How long until it hits the ground? What is the velocity of the ball as it hits the ground.


Homework Equations


What is thee formula when simplifying for T(time)?


The Attempt at a Solution


When using the formula d=ViT + 1/2a*d I get 3.4s, but the answer is 1.6s.

Welcome to PF.

Maybe think more in terms of

x = Vi*t + 1/2*g*t2
 
now I am still getig high answers... how do i simplify for t?
 
reltz said:
now I am still getig high answers... how do i simplify for t?

Didn't you get a quadratic equation? Use the quadratic formula. I don't think one of the solutions is too large.
 

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