physics

  1. I

    Steps of deriving a complicated algebra equation

    Hello guys, I am currently working on a physics paper, and in it there is an equation I need to show how to derive. The equation is (it's not in its original form because it has variables containing two letters, and even though one might say it makes no difference, it actually makes the...
  2. J

    Kinetic and Potential Energy

    Is there a chance this problem can be solved? Our Physics Dr. drew this diagram on the board and he said find vo without any further explanation! He stated that it is a complicated problem. I assume that the object will reach point B with some speed. I have Ea = mgh + (1/2)mvo^2 Eb = mgH +...
  3. W

    Newtons Third Law

    I feel like this should be easy, but I have managed to confuse myself. Please help! Five spheres, each of mass m are joined together by four in-extensible strings. The spheres hang in a vertical line as shown in the diagram and are held at rest by a force applied to the uppermost sphere, of...
  4. W

    Newtons Third Law

    in each illustrated case, the contact between the blocks and the surfaces are rough (except where indicated) The blocks are at rest and the strings are taut. Find the tension in the string and the frictional force exerted by each surface on the block with which it is in contact. I need help with...
  5. W

    terminal velocity (M1)

    A skydiver of mass m kg steps out of an aircraft and starts to fall. The air resistance when his speed is v ms^-1 is given by kv^2 newtons. If his terminal speed is 40 ms^-1, find an expression for k in terms of m. (I did this part, got (m/160), which is correct) When his speed reaches 16 ms^-1...
  6. W

    Mechanics (M!) Motion Due to Gravity

    Hi! I need help please! A particle of 0.5 kg is placed at a point O at an angle sin^-1(0.5) to the horizontal. It is projected up a track with a speed of 12m/s. There is a frictional force of magnitude 2N, which acts in a direction opposite to the direction of motion. a) Find the deceleration...
  7. W

    Resolving Forces

    Here is another one. WOw, resolving forces is really messing with my head. So...here it goes A skier of mass 78 kg is pulled at constant speed up a slope of 12 degrees, by force of 210 N acting upwards of 20 degrees to the slope. Find the magnitudes of the frictional force and the normal contact...
  8. W

    Resolving Forces

    Hello, I need help please! A particle is in equilibrium under the action of the three forces shown in the diagram. By resolving in the direction of the force of magnitude Y N, show that Y = 5. Calculate the value of X. The diagram is given below. I keep getting Y = 20. Please show the working...
  9. T

    Not understanding the physics difference between first moment and second moment.

    I know the second moment is known as the moment of inertia, and the first moment is used to find the centroid, but I'm not quite sure if I understand the conceptual understanding of the moments themselves. Here is what I think: The first moment respect so some axis is the average weighted...
  10. I

    Electric Potential Energy question HELP

    1. Two frictionless pucks are placed on a level surface, at an initial distance of 20.0 m. The mass of puck 1 is 0.80 kg and it has a charge of +3.0 x 10^-4 C while puck 2 is 0.40 kg with a charge of +3.0 x 10^-4 C. The initial velocity of puck 1 is 12.0 m/s [E] and the initial velocity of puck...
  11. P

    Physics launch of cannon ball to tower

    You are serving as a consultant for the newest James Bond film. In one scene, Bond must fire a projectile from a cannon and hit the enemy headquarters located on the top of a cliff 73 m above and 330 m from the cannon. The cannon will shoot the projectile at an angle of 34° above the horizontal...
  12. F

    Issue with gradient and divergence notation in a physics book

    (This isn't homework exactly, since it's not for a class, but it is definitely a problem from a textbook.) For some generic direction vector r = xi + yj + zk, the text book states that the div r = 3 and that grad r = r/r. (the vector is actually the position vector in the electric field given by...
  13. D

    Projectile Motion Using Vectors

    http://assets.openstudy.com/updates/attachments/51cd2a0be4b011c79f63705f-rms13-1372647113150-porh.pdf Hi I need help with question 8 in this pdf. The speed = radius(u'(t)). r=10, so u'(t)=4pi(e^-t) and u(t)=-4pi(e^-t). The position vector r(t)=<10cos(-4pi(e^-t)),10sin(-4pi(e^-t))>. How do you...
  14. L

    Integration with Physics problem

    This is the question: "A gas station stores its gasoline in a tank under the ground. The tank is a cylinder lying horizontally on its side. (iIn other words, the tank is not standing vertically on one of its flat ends.) If the radius of the cylinder is 2.5 meters, its length is 6 meters, and it...
  15. maxpancho

    Basics physics problem

    An officially sanctioned baseball must be between 142 and 149 grams. How much work, in Newton-meters, does it take to throw a ball at 80 miles per hour? At 90 mph? At 100.9 mph? What's the procedure here, can someone tell? If W=m*a*s, then could I find v, then takes it's derivative and plug...
  16. C

    2D Cannon Ball Physics: FinalY velocity at point Y

    Hi My head hurts by trying to figure this stuff out, so im asking here for advice on how to solve it ... I have a decimal coordinate system, where 0,0 starts at the top left corner. I have a Cannon in the coordinate system. The Cannon fires a Ball at an Angle and a Speed. ( I define "X/Y...
  17. L

    Distance Travelled by a Projectile (Physics)

    Hey everyone, Today we have been assigned this physics problem for homework, and I'm really stumped on how I'm supposed to figure it out. On one hand, I can see that it probably can be solved, but I have no idea how to write the equation, or series of equations, needed to solve it. That's...
  18. REDnight

    Average and Instantaneous Acceleration (physics)

    Hey guys…I got an assignment from our physics class and I was having a hard time answering this problem (Crying) . Maybe if you could lend me some of your helps and of coarse it would mean a lot to me.(Handshake)(Bigsmile)(Smile)(Smile)(Kiss) Here’s the problem: “A test driver at incredible...
  19. A

    Finding roots of a function using Brook Taylor's method(s) [Feedback]

    Finding roots of implicit functions is usually only possible by applying numerical methods that perform iterative calculations starting with a guess or seed value. If such iterative calculations converge towards a values then we assume to have found one of the roots of the underlying function...
  20. C

    Velocity of particle using graph? Physics?

    I'm not sure how to figure this out:I'm not sure how to find how far the particle with using this graph? Any help? I took physics two years ago before college and I know I learned about this but I can't remember what to do, using either physics or calc methods. Thanks!