Physics Lecture 3 Question

[SocialMed88]

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Hey SDN,

This might be a rudimentary physics question but, regardless, I still don't understand the EK explanation. Here's the question (for those that have the 7th Edition EK Physics Book, its on page 39, Q53):

https://mail.google.com/mail/?attid=0.1&disp=emb&view=att&th=130b09ceba55a4df

Thanks for the help!

 

[FIREitUP]

Hey, I just took a gander at the question and the solution is quite simple. You see that F and rad3F are perpendicular, so those two forces cannot cancel each other out at all. However, the 2F force has both x and y components to it, so we have to break it down to get the net y and x forces. To get the x force, we do cos150*2F. They give you cos150=-rad3/2 * 2F (negative gives us the direction, so we dont have to worry about the negative). The force in the x direction for this vector is therefore rad 3. Since it is opposite in direction of the rad3F and equal to rad3F, there is no net x force. Now on to the y component. To get the y component we do sin150 * 2F. They give you sin150=-.5, so .5*2F=1F in the opposite direction of the F force and equal in magnitude. Therefore, both the x and y vectors cancel each other out and there is no net force. Since there is no net force, there is no net acceleration, so C is the right answer.

 

[SocialMed88]

Got it! Thanks for the explanation. 🙂