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  1. M

    1D Kinematics

    Have you been taught all of the basic kinematic equations? If so, look at each of them. You'll find that each one has a different variable missing. Knowing this all you have to do is look for the equation with all the variables you're given and the variable you need and then use that.
  2. M

    Find the total displacement on a velocity-time graph

    Okay. You understand that, as a vector quantity, displacement is a number value representing distance combined with an angle, measured from a certain point. This problem takes away the need for an angle, because the car can only move in two directions - forward and backward. This makes it easy...
  3. M

    Find the total displacement on a velocity-time graph

    So what you don't get is the reason one of the areas subtracts from the other?
  4. M

    Find the total displacement on a velocity-time graph

    What exactly doesn't make sense? Do you understand what the product of a velocity-time actually is graph is? Are you aware of the vector nature of velocity and displacement?
  5. M

    Find the total displacement on a velocity-time graph

    Give it a crack first. Write up your attempt here :) It's against the rules of the forum to give help without the asker proving they're not just being a slacker.
  6. M

    Can anyone explain to me why this works? Calculating power w/ voltage and resistance

    Power is given by P = VI. V, voltage, is energy per charge (Joules per coulomb) I, current, is charge per time (Coulombs per second) From this we can see that if we increase the voltage, the overall energy output will increase. We can also see that if we increase the current, the same will...
  7. M

    Voltage across a transistor

    Ratch, your addressing questions to which I already know the answer. What I wanted to know was the voltage across the transistor when the LDR as at the resistances given, and why it is so. I now know that because the transistor is off 10V of potential is stored in the wire, and that 10V of...
  8. M

    Voltage across a transistor

    So basically, given the tiny current that comes about as a result of the massive resistance of the transistor, and given the tiny voltage drop across Rc that comes with this current, I can essentially look at that path through Rc to Vout as an extension of the cell.
  9. M

    Block Acceleration up an Inclined Plane

    Well static friction is the frictional force between the mass and the plane when the mass is stationary. For example if I had a 10kg mass and a Us of 0.1, the frictional force would be mg0.1. We'll take that to equal 10N because I'm feeling lazy and 9.81 is just too much. So the frictional...
  10. M

    Block Acceleration up an Inclined Plane

    Yes, however don't expect any help from me on that one. I could sit down for a while and try it but I'm by no means a physics guru like some of the people here. While you can apply the same principles, there's a few other principles you need to apply. Like force to overcome static friction etc...
  11. M

    Voltage across a transistor

    Yes. Given that potential is lost, however small an amount, across Rc, current would have to flow through it. This current cannot then flow through the transistor to lose its potential at earth.. (I now see what you're getting at. Okay, The current is actually very small.) But still, there is...
  12. M

    Voltage across a transistor

    The second paragraph and the answers to b) and c).
  13. M

    Block Acceleration up an Inclined Plane

    Take azizlwl's advice and draw a force diagram. That being, if you don't know, a simplified picture of the situation showing planes, masses and forces and any relevant angles and figures. In this case you would draw a box sitting on an inclined plane, fill in the angle of the plane and any...
  14. M

    Voltage across a transistor

    I already have done part A. That was the simple part it's just solving a voltage div equation for Vout = 0.65V. b) and c) were the problem, but I think I understand and my possible understanding lines up with the answers given. Are you able to tell me if what I said in my last post is correct?
  15. M

    Voltage across a transistor

    So does current only flow through the left side of the circuit? As that is the only path along which current can flow in light of infinite resistance from the inactive transistor and the wire that goes to nowhere. Edit. Potential brainwave. For partis and b do you just work out the voltage as...
  16. M

    Voltage across a transistor

    And what does this mean in relation to my problem? I am completely lost with this one..
  17. M

    Voltage across a transistor

    That is a good question.. Through whatever device Vout is being measured across and to earth? I am right in saying it can't flow through the transistor aren't I?
  18. M

    Capacitance and voltage relationship

    Are you reading "percentage difference" as "percentage potential difference" or something similar?
  19. M

    Capacitance and voltage relationship

    Where is that stated? If so, why is the answer given farads? Additionally, bearing in mind that I'm yet to study capacitors in any level of detail, does the voltage not correspond to a maximum input voltage that the device can handle without being damaged, destroyed, or at least cease to function?
  20. M

    Capacitance and voltage relationship

    The stated capacitance is 1000. The possible variance is -10% to +50%. What is 10% of 1000 subtracted from 1000? What is 50% of 1000 added to one thousand?
  21. M

    Block Acceleration up an Inclined Plane

    Remember that forces are vectors and can act in different directions. Think about which forces act in which direction (Up or down the hill) in the problem. The 3.5kN work to accelerate the block .... the hill, gravity and friction work to accelerate the block .... the hill. Together they make a...
  22. M

    Voltage across a transistor

    Homework Statement See attachment. Homework Equations Voltage division equation. Ohm's law. The Attempt at a Solution From a) I know that Rx = 86k ohms. Part b) and c) befuddle me. I think it is relevant to the transistor being on and off. In b) I would think that because Rx...
  23. M

    Voltage across a load resistor in a Voltage Divider Circuit

    Okay. Now I understand. Vaguely, but I think I understand. Thanks very much. I think I need to refine my basic understanding of electricity itself. I'm still in that rut where I imagine electrons coming out of a battery instead of merely being pushed/dragged along by it.
  24. M

    Voltage across a load resistor in a Voltage Divider Circuit

    Hey Nascent. Can you explain to me why the current is relative to the 2.2k as opposed to the resistor across which voltage is being measured?
  25. M

    Voltage across a load resistor in a Voltage Divider Circuit

    Homework Statement Show that V across Resistor Rkohms is: (11R) / (3.96 + 4R) V The circuit is a 5V cell in series with a 1.8k resistor. Following the 1.8k resistor are a 2.2k and Rk resistor in parallel with eachother. The wires then rejoin and return to the cell. Current through the...
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