Don't care about the work being showed right now. I just need answers by 11:59 The fifth question is attached and includes a picture. Will rep for correct answers.
2. How much work is done by the motor in a CD player to make a CD spin, starting from rest? The CD has a diameter of 12.2 cm and a mass of 15.6 g. The laser scans at a constant tangential velocity of 1.14 m/s. Assume that the music is first detected at a radius of 19.8 mm from the center of the disk. Ignore the small circular hole at the CD's center.
5. A playground merry-go-round made in the shape of a solid disk, has a diameter of 2.64 m and a mass of 350.1 kg. Two children, each of mass 30.0 kg, sit on opposite sides at the edge of the platform. Approximate the children as point masses.
(a) What torque is required to bring the merry-go-round from rest to 29 rpm in 19.5 s?
(b) If two other bigger children are going to push on the merry-go-round rim to produce this acceleration, with what force magnitude must each child push?
6. A solid sphere of mass 0.604 kg rolls without slipping along a horizontal surface with a translational speed of 5.28 m/s. It comes to an incline that makes an angle of 38? with the horizontal surface. Neglect energy losses due to friction.
(a) What is the total energy of the rolling sphere?
(b) To what vertical height above the horizontal surface does the sphere rise on the incline?
9. A uniform disk with a mass of 815 g and radius 17.0 cm is rotating on frictionless bearings with an rotational speed of 18.0 Hz when Jill drops a 105 g clod of clay on a point 7.50 cm from the center of the disk, where it sticks. What is the new rotational speed of the disk?
Last edited by Lunatic; 11-02-2009 at 10:06 PM.
RIP Slash_
If you don't know or can't figure out the differences between you're/your/there/they're/their.... please go slam your head against a brick wall.
Don't care about the work being showed right now. I just need answers by 11:59 The fifth question is attached and includes a picture. Will rep for correct answers.
2. How much work is done by the motor in a CD player to make a CD spin, starting from rest? The CD has a diameter of 12.2 cm and a mass of 15.6 g. The laser scans at a constant tangential velocity of 1.14 m/s. Assume that the music is first detected at a radius of 19.8 mm from the center of the disk. Ignore the small circular hole at the CD's center.
5. A playground merry-go-round made in the shape of a solid disk, has a diameter of 2.64 m and a mass of 350.1 kg. Two children, each of mass 30.0 kg, sit on opposite sides at the edge of the platform. Approximate the children as point masses.
(a) What torque is required to bring the merry-go-round from rest to 29 rpm in 19.5 s?
(b) If two other bigger children are going to push on the merry-go-round rim to produce this acceleration, with what force magnitude must each child push?
6. A solid sphere of mass 0.604 kg rolls without slipping along a horizontal surface with a translational speed of 5.28 m/s. It comes to an incline that makes an angle of 38? with the horizontal surface. Neglect energy losses due to friction.
(a) What is the total energy of the rolling sphere?
(b) To what vertical height above the horizontal surface does the sphere rise on the incline?
9. A uniform disk with a mass of 815 g and radius 17.0 cm is rotating on frictionless bearings with an rotational speed of 18.0 Hz when Jill drops a 105 g clod of clay on a point 7.50 cm from the center of the disk, where it sticks. What is the new rotational speed of the disk?
2. .0529550685 j
sorry dude got a test tomorrow so thats all i had time for
I have this one worked out but it's wrong. I did it the same way my fraternity brother did it but I got it wrong and he got it right.
What is the rotational inertia of a solid iron disk of mass 47 kg, with a thickness of 6.16 cm and radius of 18.8 cm, about an axis through its center and perpendicular to it?
Any help? All other problems are done.
RIP Slash_
If you don't know or can't figure out the differences between you're/your/there/they're/their.... please go slam your head against a brick wall.
EDIT: I see the time now, seems i missed it. Theres no way anyone could have answered all those in 8 minutes, unless they work on this **** regularly. Probably take half an hour just to look up the stuff again.
I have this one worked out but it's wrong. I did it the same way my fraternity brother did it but I got it wrong and he got it right.
What is the rotational inertia of a solid iron disk of mass 47 kg, with a thickness of 6.16 cm and radius of 18.8 cm, about an axis through its center and perpendicular to it?
Any help? All other problems are done.
= I = 0.5m(r^2)
= 0.830584, assuming the axis is down the middle. If its like through the side
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