physics help please

[ttran01]

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im stuck on a few problems.

a 1kg ball of radius 0.5m rolls up along an incline plane (20 degree inclination angle) for 2.5 m and then rolls back to the bottom

what is the total angular displacement
what is the angular velocity at the bottom

a hallow sphere, initially at rest, is rolling without slipping down a ramp of height 2.0m on one end.

what is the final velocity when it reaches the bottom?
what is the length of the ramp if the radius of the sphere is 5cm and it takes 5 seconds to reach the bottom.

a 1000 kg car moving at 30 m/s due south of west 30 degree runs into a second car which is moving toward east. after the collistion both cars are stuck together and moving at 17.2 m/s due south of west 35.6 degrees

what is the mass of the second car
what is the speed of the second car before collision


im pretty sure i understand the first two. i need help on the last question. then if you would like to help on the first two, thanks.

any help will be appreciated. thanks

 

[sejin8642]

im stuck on a few problems.

a 1kg ball of radius 0.5m rolls up along an incline plane (20 degree inclination angle) for 2.5 m and then rolls back to the bottom

what is the total angular displacement
what is the angular velocity at the bottom

a hallow sphere, initially at rest, is rolling without slipping down a ramp of height 2.0m on one end.

what is the final velocity when it reaches the bottom?
what is the length of the ramp if the radius of the sphere is 5cm and it takes 5 seconds to reach the bottom.

a 1000 kg car moving at 30 m/s due south of west 30 degree runs into a second car which is moving toward east. after the collistion both cars are stuck together and moving at 17.2 m/s due south of west 35.6 degrees

what is the mass of the second car
what is the speed of the second car before collision


im pretty sure i understand the first two. i need help on the last question. then if you would like to help on the first two, thanks.

any help will be appreciated. thanks

If my memory serves me right(took physics in high school), the last problem deals with vector and momentum. I think you have to use vector values and momentum formula(I think the formula was m1v1 + m2v2 = vf(m1+m2)).

 

[CSI Dentist]

no worries... no physics on DAT. lol... wrong forum!

 

[pmantz]

Basic Newtonian Mechanics.... I am so glad I don't have to waste my time with that anymore. For future reference go to Wikipedia or google your problem instead of coming to SDN. You will get much more information somewhere else and you won't have to wait for a reply.(unless you want to waste time on SDN like myself.)
My Physics text was poorly written and not worth the paper it was printed on. I found websites with BASIC problems and how to solve them. BTW physics I and II total wastes of time.

 

[MALOKINMARTIN]

I.... DON'T.... KNOW! HAHAHA No more physics for me! YAY!!! (Sorry)

 

[kappa505]

The general momentum equation is m1*V1i+m2*V2i=(m1+m2)*Vf. You need to break this equation above into the x and y vector components. So now you have m1*V1ix+m2*V2ix=(m1+m2)*Vfx and similarily for the y direction.
m1*V1iy+m2*V2iy=(m1+m2)*Vfy.


m1*V1ix this statement says, mass of object 1 times the initial velocity of object 1 in the x direction

m2*V2ix this statement says, mass of object 2 times the initial velocity of object 2 in the x direction

(m1+m2)*Vfx this statement says, mass of the total objects times the final velocity of both of the objects in the x direction

The equation for the y direction follows the exact same principal.

You calculate V1ix by taking the initial velocity of object one and multiplying it by its vector direction in the x direction, so V1ix= (30m/s)*cos30

You calculate V2ix by taking the initial velocity of object two and multiplying it by its vector direction in the x direction so V2ix=V2ix. You have to solve for this value. It is one of the two unknowns. The y direction is the same except you use sin30.

Solve this equation to get the mass of the second object.

1000*30*sin30+m2*v2*sin0=(1000+m2)*17.2*sin35. m2*v2*sin0=0 because sin0=0. you now only have one unknown namely m2. Solve for m2 and then plug that value into this equation.

1000*30*cos30+(m2value you solved for)*v2*cos0=(1000+m2value you solved for)*17.2*cos35. Now your only unknown is v2. Solve for that value.

 

[kappa505]

The general momentum equation is m1*V1i+m2*V2i=(m1+m2)*Vf. You need to break this equation above into the x and y vector components. So now you have m1*V1ix+m2*V2ix=(m1+m2)*Vfx and similarily for the y direction.
m1*V1iy+m2*V2iy=(m1+m2)*Vfy.


m1*V1ix this statement says, mass of object 1 times the initial velocity of object 1 in the x direction

m2*V2ix this statement says, mass of object 2 times the initial velocity of object 2 in the x direction

(m1+m2)*Vfx this statement says, mass of the total objects times the final velocity of both of the objects in the x direction

The equation for the y direction follows the exact same principal.

You calculate V1ix by taking the initial velocity of object one and multiplying it by its vector direction in the x direction, so V1ix= (30m/s)*cos30

You calculate V2ix by taking the initial velocity of object two and multiplying it by its vector direction in the x direction so V2ix=V2ix. You have to solve for this value. It is one of the two unknowns. The y direction is the same except you use sin30.

Solve this equation to get the mass of the second object.

1000*30*sin30+m2*v2*sin0=(1000+m2)*17.2*sin35. m2*v2*sin0=0 because sin0=0. you now only have one unknown namely m2. Solve for m2 and then plug that value into this equation.

1000*30*cos30+(m2value you solved for)*v2*cos0=(1000+m2value you solved for)*17.2*cos35. Now your only unknown is v2. Solve for that value.

 

[GoDucks69]

The general momentum equation is m1*V1i+m2*V2i=(m1+m2)*Vf. You need to break this equation above into the x and y vector components. So now you have m1*V1ix+m2*V2ix=(m1+m2)*Vfx and similarily for the y direction.
m1*V1iy+m2*V2iy=(m1+m2)*Vfy.


m1*V1ix this statement says, mass of object 1 times the initial velocity of object 1 in the x direction

m2*V2ix this statement says, mass of object 2 times the initial velocity of object 2 in the x direction

(m1+m2)*Vfx this statement says, mass of the total objects times the final velocity of both of the objects in the x direction

The equation for the y direction follows the exact same principal.

You calculate V1ix by taking the initial velocity of object one and multiplying it by its vector direction in the x direction, so V1ix= (30m/s)*cos30

You calculate V2ix by taking the initial velocity of object two and multiplying it by its vector direction in the x direction so V2ix=V2ix. You have to solve for this value. It is one of the two unknowns. The y direction is the same except you use sin30.

Solve this equation to get the mass of the second object.

1000*30*sin30+m2*v2*sin0=(1000+m2)*17.2*sin35. m2*v2*sin0=0 because sin0=0. you now only have one unknown namely m2. Solve for m2 and then plug that value into this equation.

1000*30*cos30+(m2value you solved for)*v2*cos0=(1000+m2value you solved for)*17.2*cos35. Now your only unknown is v2. Solve for that value.

Dont you have something better to do than solve physics questions for other people? I hate physics and couldnt stand doing my own homework, let alone someone else's homework.

 

[kappa505]

He needed help. And the other tools on this site were just writing stupid comments. Besides, physics rocks!

 

[dddsmack]

Physics licks

 

[DDSY]

Physics licks

Not only does physics licks, but it sucks too.

 

[superfinger45]

Not only does physics licks, but it sucks too.

plus physics smells bad and touches little kids...who wants to hang with someone like that?

 

[smec]

Physicists generally don't make much either.🙁

 

[superfinger45]

also physics smells bad

 

[rchuloholla]

CLOSEEEE this isn't dental related lol (SORRY OP LOLOLOL)

 

[dr.rex]

ok people do your own homework

 

[in her drawer]

plus physics smells bad and touches little kids...who wants to hang with someone like that?

I totally was about to post a pic . . . lol! 😡

 

[superfinger45]

I totally was about to post a pic . . . lol! 😡

Would it have been something like this?

 

[sejin8642]

You guys gotta know that other sicnece studies like biology or chemistry is a branch of physics lol.

 

[superfinger45]

You guys gotta know that other sicnece studies like biology or chemistry is a branch of physics lol.

This is how we feel about "physics"

 

[sejin8642]

This is how we feel about "physics"

That's sad. I find physics the most interesting subject.

 

[superfinger45]

 

[albodent]

I would do it again if I had take-home tests like the first time around...lol