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  1. U

    Sketch the curves y =|x| and y = 2 - x^2 on the graphs

    1. Homework Statement Sketch on the same axis the graphs of y = |x| and y = 2 - x^2. For which values f x is the inequality |x| < 2 - x^2 2. Homework Equations 3. The Attempt at a Solution I don't really understand what it is asking me to do, i've sketched the two curves...
  2. U

    Point charge and electric potential

    1. Homework Statement three point charges, each of 10^-9 are located at 3 corners of a square of side 20cm. Calculate the electric potential at the forth corner. 2. Homework Equations V = Q / (4(pi)(epsilon 0) r) 3. The Attempt at a Solution Potential because of corner A =...
  3. U

    Gas Laws

    1. Homework Statement A 200g sample of CO2 occupies a volume of 110 L at a pressure of 1 atm. a) What is the number of moles in the gas b) What is the temperature? c) if the volume is increased up to 200 L and the temperature is kept constant. what is the new pressure. 2...
  4. U

    Polar and cartesian form

    1. Homework Statement i) Express the equation r = 1 + cos(theta) in Cartesian form. ii) Sketch the curve whose equation in polar form is r = cos(theta) 2. Homework Equations x = r cos (theta) y = r sin (theta) 3. The Attempt at a Solution i) x = r cos (theta) = (1 + cos(theta)) cos...
  5. U

    Stupid question

    this will probably seem like a really stupid question but here goes. If z = 3 + 2i find the following i) z ii) z x z(with a horizontal line above it) iii) z^2 what does the horizontal bar mean, i can't find it in my reivsion books lol. Thanks
  6. U

    Electromagnatism - Find charge deos this sphere have

    1. Homework Statement The centre of a small sphere carrying a positive charge of 1.0 x 10^-8 C is fixed at 3cm above the centre of a small conducting ball, which had a negative charge and a mass of 0.05g. If the ball remains suspended, what charge does it have? Answer is [ 4.9 x 10^-9]...
  7. U

    Rates of change in volume.

    1. Homework Statement A tank is in a shape of a cylinder with a circular cross-section of area A. Initially the depth of water in the tank (the head) is h0. At time t = 0 water is allowed to leave the tank ffrom a valve at the bottom. The rate at which the water leaves the tank is...
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