A ladder of mass 30 kg and length 5m leans against a frictionless wall. The angle between the ladder and the wall is 37 degree. (a) what is the force between the ladder and the wall? (b) a 60 kg man now climbs up to the midpoint of the ladder, what is the force at the base of the ladder (magnitude and direction).? (c) what must be the coefficient of friction so that the mass can climb all the way to the top of the ladder without slipping?
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Ball 1, with a mass of 110 g and traveling at 15 m/s , collides head on with ball 2, which has a mass of 340 g and is initially at rest.
What is the final velocity of the ball 1 if the collision is perfectly elastic?
What is the final velocity of the ball 2 if the collision is perfectly elastic?
What is the final velocity of the ball 1 if the collision is perfectly inelastic?
What is the final velocity of the ball 2 if the collision is perfectly inelastic?
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(a)Two charges are placed on the x-axis: one is placed at x = 3 m and the other is at x = -3 m. The magnitude of both charges is 9.7
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n = 2.94 mol of Hydrogen gas is initially at T = 381 K temperature and pi = 2.24×105 Pa pressure. The gas is then reversibly and isothermally compressed until its pressure reaches pf = 7.63×105 Pa. What is the volume of the gas at the end of the compression process?
*****What would be the temperature of the gas, if the gas was allowed to adiabatically expand back to its original pressure?
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A:What must be the density of the oil?
B:If the vehicle is taken to Mars, where the acceleration due to gravity is 0.379 g, what will be the pressure difference (in earth atmospheres) between the top and bottom of the oil column?
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What is exponential growth? What consequences can we expect if U.S. population growth and energy consumption continue to grow exponentially? What are renewable energy sources and how can using renewable energy to generate electricity help alleviate this problem?
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Charges of the amount 45 nC/m (charge per length) are deposited at the surface of a long, straight metal wire of diameter = 2 mm in which the surrounding media is air.
(a) Which electric field and potential distribution exists
around the wire ?
(b) How large is the electric field and the surface charge density
at the wire's surface ?
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In a downhill ski race surprisingly little advantage is gained by getting a running start. This is because the initial kinetic energy is small compared with the gain in gravitational potential energy even on small hills. To demonstrate this, find the final speed and the time taken for a skier who skies 75.0 m along a 25
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Calculate the mass of the sun from the radius of the earth's orbit (1.50×1011 m), the earth's period in its orbit, and the gravitational constant G.
What is the density of the sun ? (The sun's radius is 6.96×108 m). Notice how it compares with the density of the earth.
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An isolated charged conducting sphere has a radius R = 14.0 cm. At a distance of r = 24.0 cm from the center of the sphere the electric field due to the sphere has a magnitude of E = 4.90 ✕ 104 N/C. (a) What is its surface charge density (in µC/m2)? µC/m2 (b) What is its capacitance (in pF)? pF (c) What If? A larger sphere of radius 30.0 cm is now added so as to be concentric with the first sphere. What is the capacitance (in pF) of the two-sphere system? pF
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1)suppose we start with an electron with zero initial velocity. Let ϝ be
the typical time it would take for our electron to hit an atom. We can use this as
an average time between collisions as the electron makes its way through the
material. What is the typical velocity of the electron when it hits an atom?
2) It turns out that the velocity you just calculated is not a bad estimate of the drift
velocity, vd. Now, as we saw, there is another way to write vd, namely
J = (❝ne)vd for electrons (remember J = i / A for uniform current density), where
n is the number of charge carriers (electrons) per unit volume. Solve this for |vd|
and equate with what you got in (1).
3)In the above, you should have a J on one
side and an E on the other. Now J and E
are in another important equation from today. Given that, can you
find an
expression for the resistivity of the material, ??
4)Also, we just saw in lecture that R =
(L/A)?, where L is the length of the wire and
A is its cross-sectional area. So, what
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A 1.50 kg book is sliding along a rough horizontal surface. At point A it is moving at 3.21 m/s , and at point B it has slowed to 1.25 m/s .
Part A
How much work was done on the book between A and B ?
Part B
If -0.750J of work is done on the book from B to C , how fast is it moving at point C ?
Part C
How fast would it be moving at C if 0.750J of work were done on it from B to C ?
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At an angle of 36.5deg with the horizontal, a ladder, with mass (m = 100.0 kg) rests on a frictionless wall and on the ground with a friction coefficient (μS).
a) What is the minimum value of the ladder-ground static friction coefficient if the ladder’s center of mass is located at a distance, 1/3 of its total length?
b) A boy, with mass (m = 45.0 kg), uses the ladder to retrieve a bag of 5 basketballs, each with mass (m = 0.625kg), that rests on the top of the wall. If the boy must return safely to the ground, what is the new static friction coefficient required?
c) What is the %DIFF in static friction coefficients between parts a) and b)?
d) What is the %DIFF in the magnitude of the force delivered by the wall between parts a) and b)?
e) If the boy travels at a constant velocity during his round trip travel to retrieve the ball, what is the total work done by gravity?
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Write a short paragraph on what you understand by a force field. Use gravitational and electric field concepts for your posting.
(ii) How is the concept of potential used in a force field?
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