Kinematics: Understanding the Range Formula

AI Thread Summary
The discussion revolves around the kinematics range formula R=(Vo^2)(Sin2(theta))/(g) and the confusion regarding the calculation of sin(2*28 degrees). The user initially struggles to compute the correct range, believing the issue lies with the sin(2*28) component. Clarification is provided that sin(2*28 degrees) equals approximately 0.829, which is crucial for obtaining the correct answer. The user successfully resolves their confusion about the calculator's input, confirming the correct evaluation of sin(2*28). Understanding the sine function's double angle is essential for accurate calculations in projectile motion.
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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