How Accurate Are My Initial Velocity and Maximum Height Calculations?

[bwilhelm]

Am I anywhere near correct?

Homework Statement

A ball is thrown and upward and reaches it's maximum height in 1.80 sec.

A. Find Initial Velocity
B. Find Max Height Reaced
C. Find Velocity 1.15 sec after being thrown.

Homework Equations

The Attempt at a Solution

A. .5(-9.8)*1.8^2= -15.87 m/sec
B. -15.87+.5(-9.8)*1.8^2 = 31.74m
C. .5(-9.8)1.15^2= -6.48 m/sec

 

[learningphysics]

No, not near correct. For part a, you used a displacement formula... so the result won't be a velocity...

Hint: for part a) use the fact that v2 = v1 + at. You know v2, a and t... use those to calculate v1.

For part b) you made a mistake with the formula... it should be s = v1*t + 1/2 at^2... you didn't multiply v1 by t... and also the v1 is wrong since part a was wrong...

For part c)... here again you use a displacement formula... so the result that comes out will be displacement not a velocity... 1/2 at^2 is a distance not a velocity.

 

[m2003]

Your calculations for parts A, B, and C appear to be correct. However, without any context or additional information, it is difficult to determine if your answers are correct. It would be helpful to know what type of problem this is (e.g. physics, kinematics, etc.) and if there are any given values for initial velocity, acceleration, or other relevant variables. Additionally, it is important to label your units in your calculations to ensure accuracy. Overall, it seems like you are on the right track but it would be beneficial to provide more context and information for a more accurate response.