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anonymous
 4 years ago
The position of a particle as a function of time is given by r_vec =( 6.60 \hat{ i }+ 2.40 \hat{ j })t^{2}\;{\rm m}, where t is in seconds.
What is the particle's speed at t_1 = 2.20 s?
anonymous
 4 years ago
The position of a particle as a function of time is given by r_vec =( 6.60 \hat{ i }+ 2.40 \hat{ j })t^{2}\;{\rm m}, where t is in seconds. What is the particle's speed at t_1 = 2.20 s?

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anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Take the derivative with respect to time of rvector to get the velocityvector. To take the derivative, take the derivative of each dimensional component. For instance, the x component 6.60's derivative is 0, so the velocity's x component is 0. The y component 2.4t^2 can be differentiated to to 4.8t. Being that it's a vector, you should create a right triangle with both components and solve for the hypotenuse (final vector), but there's no x component so just plug in 2.2 for t in 4.8(t) for your answer.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0someone else posted this question or similar. anyway, basically didnt read the previous answer but i did see derivative. which is what u need to do. first derivative. then just plug in ur t and getv :) eazy peazy :)

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0that didnt work. i had tried that already. when you take the derivative of (6.6+2.4)t^2 you get 13.2t+4.8t which would be your velocity at at 2.2 seconds your speed should be 39.6. BUT doing this on mastering phyusics it tell me the answer is incorrect.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0You're multiplying wrong. I got a solution of 10.56.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Actually, that was an unhelpful answer. Give me some time to do it all out.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0the correct answer is 30.9

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0which equates to \[\sqrt{6.6^2 + 2.4^2} *2.2 * 2\] where 2.2= t and 2 came from the derivative

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Huh, could you type out your problem without using LaTeX? Maybe it copied badly in your asking of it.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0This should be able to solve any "find the velocity given this position vector" in 2D.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0\[r=(6.6 i + 2.4 j)t^{2}\]
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