Search results

  1. A

    Satellite orbiting Earth

    Question: A 460kg satellite is launched into a circular orbit and attains an orbital altitude of 850km above Earth's surface. Calculate the: e) additional energy and speed required for the satellite to escape. Attempt: I found Ek to be 1.27*10^10 J Thus, the total energy is...
  2. A

    Negative maximum kinetic energy in Millikan's data?

    What am I finding to be confusing.. The graphs of Millikan's data were straight lines with equal slopes. The graph was plotted maimum kinetic energy (eV) versus the frequency of the wave. This was the graph that produced the linear relationship from the photoelectric effect. What does it mean...
  3. A

    Fletcher's trolley apparatus - maximum value of coefficient

    Homework Statement A Fletcher's trolley apparatus is set up with a block of wood of mass 4.0kg and a suspended mass of 2.0kg. The Attempt at a Solution a) Calculate the acceleration of the sys. and the tension in the string when the mass is released. m1 FnetX = [T - Ff = m1(a)] FnetY...
  4. A

    Quick question about inertial frames of reference

    Homework Statement If you are on the merry-go-round going in a circle at constant speed, are you looking at the world in an inertial, or non-inertial frame of reference? How do we tell whether from one's viewpoint, they are looking at something from an interial or non-inertial frame of reference?
  5. A

    Guy pushing girl on a swing models h.displacement with function

    1,2,3. Homework Statement , and work done. After Lee gives his little sister Kara a big push on a swing, her horizontal position as a function of time is given by the equation x(t) = 3cost(t)*e^{-0.05t} , where x(t) is her horizontal displacement, in metres, from the lowest point of her swing...
  6. A

    Sun radiating energy at a rate

    Homework Statement The Sun radiates away energy at the rate of 3.9*10^24 Watts. At what rate it it losing mass due to this radiation? Homework Equations E = Δmc^2 E = mc^2 - m0c^2 Where m0 rep. rest mass. The Attempt at a Solution For this one, I am unsure as to how I would go...
  7. A

    Neutron must travel so that kinetic energy = rest energy

    Problem statement How fast must a neutron be travelling relative to a detector in order to have a measured kinetic energy that is equal to its rest energy? An "attempt" I know Ek = mc^2 - m0c^2 But if Ek = m0c^2, wouldn't the two terms cancel out from this equation? I am having trouble...
  8. A

    Simplest Way of finding zeros of cubic eq when rational roots test fails

    Homework Statement Find the zeros of the cubic equation: y = x^3 -9x^2 + 15x + 30 How do we find the zeros of this? In this case, subbing in x-values that will make it equal 0 does not work.
  9. A

    Help with understanding Young's Derivation

    Homework Statement Here they are deriving the equation for Young's experiment: http://www.physicsclassroom.com/Class/light/U12L3c.cfm The part where they start bringing up "Assertion" and "Logic/Rationale" is where I got confused: They mention for part ii) that if the distance L >>> y, then...
  10. A

    Sketch this curve (two multipled root functions)

    Homework Statement Sketch the curve defined by g(x) = x^{1/3}*(x+3)^{2/3} Homework Equations First Derivative Second Derivative The Attempt at a Solution I attempted to use the algorithm for curve sketching: 1) Find the intercepts 2) First Derivative; look for extrema and points where f'(x)...
  11. A

    What force would be this replaced charge experience?

    Homework Statement A charge q1 = +4.0nC experiences a force of 3*10^-5N to the east when placed in an electric field. If the charged is replaced by another, q2 = -12nC, what will be the magnitude and direction of the force on the charge at that position? Homework Equations Coulomb's Law...
  12. A

    [Please delete old thread] Kid going down slide

    Homework Statement A parent takes their child to a water slide which is shaped similar to a portion of a parabola (see diagram). There is an elevator 3m from the edge of the pool. The elevator takes the rider to the top of the slide which is 19m above ground. The rider slides down and falls...
  13. A

    Find the minimum distance from a curve to a point not on it

    Homework Statement You are given point (1,2). f(x) = 0.199445983x^2 - 3.789473684x + 19 f'(x) = 0.398891966x - 3.789473684 You also know (0,19), (9.5,1) <-- this is the vertex. This graph has the domain 0≤ x ≤ 9.5 Find the point on the curve that when joined to a line segment with...
  14. A

    Kid going down slide

    Homework Statement A parent takes their child to a water slide which is shaped similar to a portion of a parabola (see diagram). There is an elevator 3m from the edge of the pool. The elevator takes the rider to the top of the slide which is 19m above ground. The rider slides down and falls...
  15. A

    Total Electric Potential, when is it zero?

    Homework Statement A charge of +6.0µC at point A is seperated 10.0 cm from a charge of -2.0µC at point B. At what locations on the line that passes through the two charges will the total electric potential be 0? The Attempt at a Solution [(+) A] ------------------------------ [(-) B] I...
  16. A

    Find the electric field intensity at point D

    [b]1. The problem statement, all variables and given/knownThe diagram shows three small charges at three corners of a rectangle; charge A is -12µC, charge B is -15µC and charge C is +8.1µC. Calculate the magnitude and direction of the electric field intensity at the fourth corner, D. The...
  17. A

    Need help understanding this concept on field intensity

    Homework Statement We are looking at gravitational field intensity in particular here, and using the earth as an example. The question states: Calculate the gravitational field intensity at a height of 300.0 km from Earth's surface. Why is it that: Since the point in question is outside of...
  18. A

    Collection of Charges

    Homework Statement Two more +Q charges are held in place the same distance "s" away from the +q charge as shown. Consider the following student dialogue concerning the net force on the +q charge: The two added charges are written with blue Q's Student 1: "The net electric force on the +q...
  19. A

    Coulomb's Law Question

    I didn't use latex because for some reason, a term with the 10 to the power of -# isn't working properly: 1.0*10^-1 Homework Statement Two identical objects have charges +6.0 microcoulombs and -2.0 microcoulombs, respectively. When placed a distance "d" apart, their force of attraction is...
  20. A

    Question about this Concept about Coulomb's Law

    Homework Statement Strictly speaking, the description of Coulomb's law given on the previous page (written below this paragraph) is meant to apply to point charges. However, just as Newton was able to develop the mathematics(calculus) that proved the mass of any spherical object can be...
  21. A

    Evaluate this limit with square roots

    Homework Statement $ \lim_{x\to0}\frac{\sqrt{x+1} - \sqrt{2x+1}}{\sqrt{3x + 4} - \sqrt{2x+4}} The Attempt at a Solution Ok, I just want to know what is the easiest approach tactic one could take to solve this. I tried doing the conjugate to rationalize the denominator, but then...
  22. A

    Momentum conserved on inclined ramps?

    Homework Statement Is momentum conserved if an object is rolling down an inclined plane? This is just a question that I was thinking over in class the other day, because the most of the coursework done was involved with collisions between two objects. Wouldn't this also be considered the...
  23. A

    Pioneer 10 Spacecraft travelling in space

    Homework Statement To escape from the solar system, how fast did the Pioneer 10 have to be travelling as it passed the orbit of Jupiter? Assume the mass of the solar system is essentially concentration in the Sun. The mass of the Sun is 1.99 x 10^30 kg and the radius of Jupiter's orbit is 7.78...
  24. A

    Work required to lift object from earth's surface to circular orbit

    Homework Statement How much work must be done by a rocket engine to lift a 1000kg payload from rest on the earth's surface to a circular orbit of radius 2Re (2 times the radius of the earth)? Homework Equations Eg = -GmM/r Ek = GmM/2r The Attempt at a Solution I know ΔE = W I...
  25. A

    Object being launched into space

    Homework Statement Complete the chart for a 1kg rock and its trip through the earth's gravitational firled. The rock was powerfully launched straight up from the surface of the earth at 1x10^4 m/s. Note: An object's kinetic energy must be a (+)-value; a negative value is impossible...
  26. A

    Dunk on the basketball net

    Homework Statement A basketball player dunks the ball and momentarily hangs from the rm of the basket. Assume that the player can be considered as a 95.0kg point mass at a height of 2.0m above the floor. If the basket rim has a spring constant of 7.4 x 10^3 N/m, by how much does the player...
  27. A

    Water going down a waterfall, where is it warmer?

    Homework Statement Consider a waterfall that is 120m high. How much warmer is the water at the bottom of the waterfall than at the top? The specific heat capacity of water is 4186J/ kg*°C. Homework Equations Conservation of Energy The Attempt at a Solution Eg [top] = Ek [just...
  28. A

    Friend pulls the spring without you looking

    Homework Statement 0.500kg mass resting on frictionless surface is attached to a horizontal spring with a spring constant of 45N/m. When you are not looking, your lab partner pulls the mass to one side and then releases it. When it passes the equlibrium position, its speed is 3.375m/s. How far...
  29. A

    Bungee Jumper - Elastic Potential Energy

    Homework Statement In a "head dip" bungee jump from a bridge over a river the bungee cord is fastened to the jumper's ankles. The jumper than steps off and falls towards the river until the cord becomes taut. At that point, the cord begins to slow the jumper's decent, until his head just...
  30. A

    Find speed of rollercoaster on point on loop

    Homework Statement 1000kg rollercoaster starts from point A on a frictionless track with the profile shown below. c) Determine the rollercoaster's speed at point B? <-- the point on the loop itself Will it work if I apply Conservation of Energy, being: from A, Ek is 0 (Starting...
Top