<p>I am having trouble with a few physics problems that I have to do for summer before I take Physics C when school starts, and was wondering if you guys can help me out. The 2 chapters I am having trouble with are vectors and universal gravitation. I need help with only 7 of the 97 I had to do from 11 chapters(crazy I know).</p>
<p>Vector problems
27. Three people attempt to haul a heavy sign to the roof of a building by using three ropes attached to a sign. Abby stands directly above the sign and pulls straight up on the rope. The other 2, Eric and Kim stand on either side of Abby. Their ropes form 30.0 degree angles with Abby’s rope. A force of 102N is applied on each rope. What is the net upward force acting on the sign?</p>
<li><p>Joe wishes to hang a sign weighing 750N so that Cable A attached to the store makes a 30.0 degree angle. Cable B is attached to an adjoining building. Calculate the necessary tension in Cable B. </p></li>
<li><p>You slide a 325N trunk up a 20.0 degree inclined plane with a constant velocity by exerting a force of 211N parallel tothe inclined plane.
A) What is component of the trunks’s weight parallel to the plane?
B) What is the sum of your applied force, friction, and the parallel component of the trunk’s weight? Why?
C) What is the size and direction of the friction force?
D) What is the coefficiant of friction.</p></li>
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<p>Universal Gravitation problems
3. Venus has a period of revolution of 225 earth days. Find the distance between the sun and Venus, as a multiple of Earth’s orbital radius.</p>
<li><p>Mimas, a moon of Saturn, has an orbital radius of 1.87 X 10^8 m and an orbital period of about 23 h. Use Newton’s verson of Kepler’s 3rd law and these data to find the mass of Saturn.</p></li>
<li><p>How high does a rocket have to go above the Earth’s surface until it’s weight is half what it would be on Earth?</p></li>
<li><p>The forumla for the period of a pendulum is T = 2pi *sqroot of( l/abs(g))
A) What would the period be of a 2.0 m long pendulum on the moon’s surface? The moon’s mass is 7.34 X 10^22 kg and its radius is 1.74 X 10^6 m.
B) What is the period of this pendulum on Earth?</p></li>
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<p>ANY help will be greatly appreciated. Do any problem(s) you want. But I also need to understand them so if you could explain them. I really will love you guys if you can help me out. THANKS!</p>