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July 27, 2025, 11:51:04 pm
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Author Topic: Foundation(VCE) Physics Questions :S  (Read 6136 times)  Share 

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bucket

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Foundation(VCE) Physics Questions :S
« on: March 16, 2009, 07:11:44 pm »
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Mmm I really did not know where to post this question, it's a university subject but at VCE level I assume.

"Vector is 8.08 units long and points along the negative x-axis, Vector is 4.51 units long and points at +45o to the positve x-axis. Determine the sum of the two vectors."
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TrueTears

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Re: Foundation(VCE) Physics Questions :S
« Reply #1 on: March 16, 2009, 07:19:07 pm »
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now just add those 2 and this yields

To work out basically just draw the vector and use trignometry.



x = 3.189 (3 dp)



z = 3.189(3 dp)

« Last Edit: March 16, 2009, 07:21:27 pm by TrueTears »
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bucket

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Re: Foundation(VCE) Physics Questions :S
« Reply #2 on: March 16, 2009, 07:21:08 pm »
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Apparently the answer is 5.84 and 33.1o above -x-axis
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TrueTears

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Re: Foundation(VCE) Physics Questions :S
« Reply #3 on: March 16, 2009, 07:22:54 pm »
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Quote from: bucket on March 16, 2009, 07:21:08 pm
Apparently the answer is 5.84 and 33.1o above -x-axis

yeap then just do this

let the vector sum be

so

now

to work out the angle, again draw the vector Y then use trig

so,



both way are acceptable. I guess I should have answered in this format because the question state the vectors like that, so yeah |Y| means the magnitude of Y, ie the length in units, and the angle is just how far up it is from the x axis ( in this case it's from the negative x axis)
« Last Edit: March 16, 2009, 07:26:25 pm by TrueTears »
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bucket

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Re: Foundation(VCE) Physics Questions :S
« Reply #4 on: March 16, 2009, 07:25:35 pm »
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Perfect!
Cheers mate.
Man I feel so dumb for not being able to do this stuff :p

MAN ITS SO SIMPLE!! AHRHJKFHGJKFHGJKF lol

« Last Edit: March 16, 2009, 07:31:57 pm by bucket »
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TrueTears

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Re: Foundation(VCE) Physics Questions :S
« Reply #5 on: March 16, 2009, 08:30:57 pm »
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Quote from: bucket on March 16, 2009, 07:25:35 pm
Perfect!
Cheers mate.
Man I feel so dumb for not being able to do this stuff :p

MAN ITS SO SIMPLE!! AHRHJKFHGJKFHGJKF lol


lol I always make stupid mistakes, asif blame yourself over this question haha maybe you were just stomped :P
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enwiabe

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Re: Foundation(VCE) Physics Questions :S
« Reply #6 on: March 16, 2009, 09:29:30 pm »
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do you have ali moghimi
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bucket

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Re: Foundation(VCE) Physics Questions :S
« Reply #7 on: March 22, 2009, 02:38:39 pm »
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What is the maximum speed with which a 1050kg car can round a turn of radius 70m on a flat road if the coefficient of friction between tires and the road is 0.80? Is this result independent of the mass of the car?
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TrueTears

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Re: Foundation(VCE) Physics Questions :S
« Reply #8 on: March 22, 2009, 02:49:00 pm »
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Yes this is independent of the car's mass



(let = coefficient of friction = 0.80)

N is normal force = mg

equating yields

But



the mass cancels which leaves us with:



to work out max speed, sub in the values and work out v :)
« Last Edit: March 22, 2009, 02:50:43 pm by TrueTears »
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bucket

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Re: Foundation(VCE) Physics Questions :S
« Reply #9 on: March 22, 2009, 02:53:40 pm »
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ahhh how do you guys learn how to approach these problems :S it's impossible for me to teach myself this !!
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TrueTears

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Re: Foundation(VCE) Physics Questions :S
« Reply #10 on: March 22, 2009, 02:57:07 pm »
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Just mess around with the equations :P

EDIT: what the... I am starting to see red boxes for LaTeX now lol
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bucket

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Re: Foundation(VCE) Physics Questions :S
« Reply #11 on: March 22, 2009, 02:58:31 pm »
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I get confused whenever I'm faced with a question involving friction :S. How do you work out friction required to round a curve? Does the force of the friction have to be the same as the centripetal force?? lol


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TrueTears

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Re: Foundation(VCE) Physics Questions :S
« Reply #12 on: March 22, 2009, 03:04:00 pm »
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Quote from: bucket on March 22, 2009, 02:58:31 pm
I get confused whenever I'm faced with a question involving friction :S. How do you work out friction required to round a curve? Does the force of the friction have to be the same as the centripetal force?? lol




Assuming constant circular motion.
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bucket

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Re: Foundation(VCE) Physics Questions :S
« Reply #13 on: March 22, 2009, 03:08:22 pm »
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hmm, I see.

I have another question lol...
"A 1000kg sports car moving at 20m/s crosses the rounded top of a hill (r=100m). Determine the normal force on the car."

When I tried to do this question I assumed mg=FN which was obviously wrong and stupid to do... but I have no idea how else to approach this!
The answer is 5800N
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Re: Foundation(VCE) Physics Questions :S
« Reply #14 on: March 22, 2009, 03:11:35 pm »
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hint: use
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