Kinematics: Understanding the Range Formula

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Homework Help Overview

The discussion revolves around a kinematics problem involving the range formula for projectile motion, specifically focusing on the evaluation of the sine function within the formula.

Discussion Character

  • Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants explore the interpretation of the sine function in the range formula, particularly questioning the meaning of "sin2(28)" and its evaluation. There are inquiries about potential calculator mode issues affecting the results.

Discussion Status

Participants are actively engaging with the problem, sharing their calculations and results. Some have provided specific values for the sine function, while others are seeking clarification on calculator usage and the evaluation process.

Contextual Notes

There is a noted uncertainty regarding the calculator settings (radians vs. degrees) and how this may impact the calculations being performed.

ThomasMagnus
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For a kinematics question, I am using the range formula:

R=(Vo^2)(Sin2(theta))/(g)

With my values in the equation I get: Square root of((7.80)(9.80)/(Sin2(28))
The correct answer is 9.60. I can't seem to get this answer. I believe it is the "Sin2(28)" part. What does this mean? Does this mean sin56? 2xsin28? Would you be able to explain what this means?

Thanks!
 
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It means,

Range = \frac{V_o^2 \; sin(2 \theta)}{g}
 
Sorry, I'm having trouble understanding. This kind of set up is new to me. I can't seem to get the correct answer when I plug it into my calculator. Does it have anything to do with the calculator being in radian or degree mode?

Thanks!
 
When I do it, I get 8.84, but the correct answer is supposedly 9.60
 
What I am asking is: how do you evaluate sin2(28)?

Thanks
 
ThomasMagnus said:
What I am asking is: how do you evaluate sin2(28)?

Thanks

sin(2 * 28 degrees) = 0.829
 
gneill said:
sin(2 * 28 degrees) = 0.829

What would be the keystrokes for the calculator?

Thanks!
 
Wait I got it :)

Sin(2x28)=0.829

Thanks for the help!
 

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