Recent content by kurtlau

  1. K

    Can anyone tell me which content of astronomy's book or magzine is the best?

    can anyone tell me which content of astronomy's book or magzine is the best? thank you
  2. K

    What is the average pulling force?

    thank you very much
  3. K

    What is the average pulling force?

    COULD ANYONE PLEASE ANSWER ME FOR I DON'T UNDERSTAND WHY SHOULDN'T WE CONSIDER mgsin(angle) and friction AS WELL? At the top of a slope, a trolley(mass:20kg) is released from rest and slides down freely along the slope (the runway is 25m long and makes an angle of 15 degrees with the...
  4. K

    Projectile fired - find maximum height

    (9) A projectile is fired with a initial speed of 75.2 m/s at an angle of 34.5^o above the hotizontal on a long flat firing range. Determine (a) the maximum height reached by the projectile, (b) the total time in the air, (c) the total horizontal distance covered(that is, the range), (Ans...
  5. K

    Undergrad Calculate Temperature at Bottom of 100m Waterfall: Help Needed!

    A waterfall is 100m high and the temperature of the water at the top is 12℃.Assume that all the kinetic energy of the water reaching the bootom is changed into internal energy. Find the temperature of water at the bottom of the waterfall. I don't know how to calculate~ Help me please and...