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  1. A

    Pulley and circular motion

    Homework Statement There is a block of known mass m on a horizontal surface. The block is connected to a pulley via a rope. The other end of the rope is pulled vertically, downwards, with a known force F. The pulley has a known moment of inertia I and radius r. Calculate the acceleration a of...
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    Torque with "complex" object (static/equilibrium)

    I have a general understanding of how torque works, at least for "simple" objects that can be drawn as a single "bar" under the effect of various forces. In this problem there is a slightly more "complex" object though, and I'd like to know if there is a way to solve it without doing what I did...
  3. A

    Vertical circular motion in container

    Homework Statement We have an object rotating inside a circular container. The rotation is vertical (see picture below). The radius r of the container is given. Find the frequency (which then ties back to finding the centripetal acceleration) necessary, so that the objects rotating inside the...
  4. A

    Circular Motion - Hanging object swinging around

    Homework Statement An object of mass m is rotating, hanging from a string of known length l. The string is attached to a pole, which rotates with a known angular velocity ω and forms a to-be-determined angle α with the string. Find α. I think I have solved it (the numbers match the results of...
  5. A

    Circular Motion — Object on a rotating conic surface...

    I need help understanding what kind of problem this is at all, since I'm really lost. I'm missing the specific topic name (I called the topic "circular motion" because it's got something to do with it, but maybe it has a more specific sub-topic name), probably missing key formulas, and generally...
  6. A

    Sign of a function

    Homework Statement ##y = \sqrt {x+5} + \sqrt[3] {\frac {x} {4}}## Find when the function is positive/negative/zero. We were actually supposed to only calculate the domain in this exercise, but we had done some simpler and more basic positive/negative calculations before, and I was curious...
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    Irrational equation

    I figured it out >_> I got a problem with discarding the second solution of this irrational equation: ##-\sqrt {x^2 - 1} + \sqrt {x^2 +3x} = 2## First I find the domain, which will end up being ##x\leq-3## v ##x\geq+1## since that's the common union of the domains of each square root. Then I...
  8. A

    Friction Force with Incline and Pulley

    Homework Statement There is a mass m1 on an incline (angle α), connected to a pulley with a string, and on the other side of the pulley, after another string, there is a mass m2. See picture if it's unclear, I'm not sure how to express the problem. Anyway the plane has a friction coefficient...
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    Incline and Friction direction

    Homework Statement It's Problem 3 of this page: http://www.problemsphysics.com/forces/inclined_planes_problems.html "A box of mass M = 10 Kg rests on a 35° inclined plane with the horizontal. A string is used to keep the box in equilibrium. The string makes an angle of 25 ° with the inclined...
  10. A

    Thermal expansion

    Homework Statement A one-liter pot is completely filled with oil. Heat is applied to the pot&oil and the temperature rises from 15°C to 190°C. How much oil is spilled over? The linear coefficient of thermal expansion for oil is 0.68*10-3; the one for the pot is 2.4*10-5 Homework Equations...
  11. A

    Two-value system with square roots

    Homework Statement I have a problem with lines in analytic geometry, and I solved it in a certain way (parallel lines interceptions) which gives the correct result, and I'm happy with that. There was another method I thought I could use to solve it though, which went through the formulas of...
  12. A

    Parallelogram area (coordinates)

    Homework Statement The coordinates of the parallelogram ABCD are: A (-2; 1) B (5; 2) C (6; 5) D (-1; 4) We also know that the diagonals intercept in the middle of each other (so if the diagonals are AC and BD, and the intercept in point M, then AM = MC, and BM = MD). Not sure if this...
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    Geometry problem (rectangles)

    There are three "concentric" rectangles, one inside the other, like in this figure: The image is not perfect, but we know that the distance between the sides of the inner-most rectangle and the middle rectangle is always "X", while the distance between the middle rectangle and the outer...
  14. A

    B Basic geometry problem with triangle

    This is a problem I thought of, and I was wondering how to mathematically solve it with an equation. I tried calling one leg x. So the other leg, because of Pitagora's theorem, is: √(52 - x2) The area is equal to the product of the legs divided by two, so: 6 = (x * √(52 - x2))/2 12 = x * √(52...
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    Work by a spring

    I think I solved this correctly, but it puzzles me why they made two separate questions for the first two points. 1. Homework Statement A block of known mass m is attached to the free end of a spring, on a flat horizontal surface without friction. The spring is compressed by a known distance...
  16. A

    Power, Work, friction

    Homework Statement A tractor moves, at constant velocity, on a flat surface with known friction coefficient μ (0.24), ten objects each of which has known mass m (12 kg). It does so for a known distance d (500 m), and it takes known time t (150s) to do so. Calculate the Power of the tractor...
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    Work with friction

    Hi. The problem is really simple I think, but I feel like the text is wrong even though the result seems to be correct. 1. Homework Statement An object of known mass m (71.5 Kg) is pushed on a [flat] surface with a known friction coefficient of μ (0.272). How much does the object move with a...
  18. A

    Block with "incline Force" - 3

    Homework Statement A block of mass m1 (8.5 kg) lies on a flat (non-incline) plane, with friction coefficient μ (0.2). It is pulled by a force F (32 N) that has makes an angle α (22°) with the plane. Determine: - Acceleration - After how much time t the body will have a velocity v = 1.2 m/s2...
  19. A

    Incline and Pulley - 2

    Homework Statement On an incline plane of known angle α (30°) lies a block of mass m1 (0.23 grams), connected through a pulley without friction to a second block of mass m2 (0.18 grams). Determine: - The acceleration of the block - The Tension force - The Normal force of the plane Homework...
  20. A

    Blocks/Forces - 1

    Homework Statement Two blocks of known mass m1 (20 kg) and m2 (32 kg) are at direct contact with each other, on a non-incline surface, and they are pushed by a Force F applied on the bigger block (m2). Knowing that the resulting acceleration of the Force is a (1.2 m/s2), determine: - The...
  21. A

    Inclined plane/forces exercises

    Hello everyone, I have a few problems to solve and questions that need answers. The topic is: basic Force exercises and basic applications of the Newton laws. While the general principles are somewhat clear to me, certain types of exercises confuse me to the point where I simply cannot seem to...
  22. A

    Equilibrium and Torque

    There is a stick of known length l and known mass m1 with its balance point in the middle. By placing an object of unknown mass m2 at the far end of the stick, the balance point moves towards the same end as the object by a distance of d. Calculate m2. Second, similar exercise: Stick of known...
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