Recent content by zumi78878

  1. Z

    Finding Period of Pendulum with r, m, L, M

    thanks so much for ur help! really appreicate it. glad there are people like you out there. but last question, can you explain why it has a negative sign in Torque = -mgLsinθ?
  2. Z

    Finding Period of Pendulum with r, m, L, M

    wen i plug m into the formula, T = 2∏√(I/mgL) do i use the mass of the entire system? so 1.2 + 0.8 = 2kg?
  3. Z

    Finding Period of Pendulum with r, m, L, M

    L = [(1.2*0.6)+(0.8*(0.4/2)]/(1.2+0.8) = 0.44m?using parallel axis theorem: I of disk = 1/2MR2 + ML2= 1/2(1.2)(0.2)2 + (1.2)(0.6)2= 0.456? I of thin rod = 1/3ML2 = 1/3(0.8)(0.4)2= 0.0427? I total = 0.4987? I have an exam in 45 minutes so i really need to get this cleared up before that.
  4. Z

    Solve Physics Homework: Pendulum Tension Force

    cylinder: I = 1/2 mr2 sphere: I = 2/5mr2 is rotational inertia same as moment of inertia? okay i did some calculations and this is what i got: sphere: v2=(10/7)*g*h cylinder: v2=(4/3)*g*h so the sphere has the greatest velocity and should reach the bottom first? and now with that, comes...
  5. Z

    Finding Period of Pendulum with r, m, L, M

    T = 2∏√(I/mgL) L represents the distance to the center of mass of the system? L = [(1.2*(0.4+0.6)/2)+(0.8*(0.4/2)]/(1.2+0.8) = 0.38m? using parallel axis theorem: I = 1/2MR2 + ML2 = (0.5)(1.2)(0.2)2 + 0.8(0.2+0.4)2 =0.312?
  6. Z

    Solve Physics Homework: Pendulum Tension Force

    cylinder: I = 1/2 mr2 sphere: I = 2/5mr2 is rotational inertia same as moment of inertia? okay i did some calculations and this is what i got: sphere: v2=(10/7)*g*h cylinder: v2=(4/3)*g*h so the sphere has the greatest velocity and should reach the bottom first? and now with...
  7. Z

    Finding Period of Pendulum with r, m, L, M

    Homework Statement The pendulum shown below right consists of a uniform disk with radius r = 20.0 cm and mass m = 1.2 kg attached to a uniform rod with length L = 40 cm and mass M = 0.8 kg. What is the period of the motion? Homework Equations T = 2∏√(I/mgL) The Attempt at a...
  8. Z

    Solve Physics Homework: Pendulum Tension Force

    Homework Statement A sphere and a cylinder of equal mass and radius are simultaneously released from rest on the same inclined plane and roll without sliding down the incline. Then: A. the sphere reaches the bottom first because it has the greater inertia B. the cylinder reaches the bottom...
  9. Z

    How Does Projectile Motion Affect Internal Energy Changes?

    Thanks so much! I feel like I know so much more now. Hope I do well on the exam tmr! :)
  10. Z

    How Does Projectile Motion Affect Internal Energy Changes?

    so is the answer for #2 wrong? answer says that it decreases internal energy. and mu prof just replied to my email, and he said that the ans for both ques is that internal energy decreases in both cases? now I am really confused... but your answer makes so much sense. the new kinetic energy...
  11. Z

    How Does Projectile Motion Affect Internal Energy Changes?

    Umm no i don't know what internal energy is, can you please explain? I just did 1/2(5)(1502-2002) = -43750J but why is the answer positive? the energy turns into heat? but does it go into the surroundings? and why is this answer negative and not positive? ummmm i can't think of it :S work =...
  12. Z

    How Does Projectile Motion Affect Internal Energy Changes?

    Homework Statement A 5-kg projectile is fired over level ground with a velocity of 200m/s at an angle of 25◦ above the horizontal. Just before it hits the ground its speed is 150m/s. Over the entire trip the change in the internal energy of the projectile and air is: A. +19, 000 J B. −19, 000 J...
  13. Z

    Spring Physics Help: Initial Velocity & Max Accel.

    A 5-kg projectile is fired over level ground with a velocity of 200m/s at an angle of 25◦ above the horizontal. Just before it hits the ground its speed is 150m/s. Over the entire trip the change in the internal energy of the projectile and air is: A. +19, 000 J B. −19, 000 J C. +44, 000 J...
  14. Z

    Spring Physics Help: Initial Velocity & Max Accel.

    As shown, block 1 has mass m1=460 g, block 2 has mass m2=500 g, andthe pulley which is mounted on a horizontal axle with negligible friction has mass M = 92kg and radius R=5.00 cm. The moment of inertia of the pulley is I = 1/2MR^2. When released from rest,block 2 falls 75.0 cm in 5.00 s...
  15. Z

    Spring Physics Help: Initial Velocity & Max Accel.

    yeah i realized that the book has a lot of wrong answers. i have my exam tomorrow and i don't even know what's wrong and what's right...
Back
Top