quiz9

  1. A 30kg child sits on a big uniform see-saw at a distance of 4.00m from the axis. The axis is through the center. How far from the axis on the other side must an average 60kg physics student sit (this is not the lever arm) to balance this system at 30degrees to the horizontal? Also what is the magnitude of the torque applied by the physics student?
    a) 8.00m, 480Nm
    b) 2.00m, 120Nm
    c) 1.732m, 103.9Nm
    d) 2.00m, 1018Nm
    e) 1.732m, 1018Nm
    No answer given yet
  2. A 5 kg mass is located at x(1)=0.100m and y(1)=0.200m. A 15 kg mass is located at x(2)=0.30m and y(2)=0.00m. A 10kg mass is at x(3)=-0.30m (see that minus sign) and y(3)=0.10m. What is the center of mass position of this system? (give x then y)
    a) 0.000m, 0.1500m
    b) 0.0667m, 0.0667m
    c) 0.0667m, 0.1333m
    d) 0.1000m, 0.3000m
    e) 0.0000m, 0.0000m
    No answer given yet
  3. In problem 2 above, what is the moment of inertia about the origin for that system?
    a) 2.200 kg m^2
    b) 2.600 kg m^2
    c) 8.000 kg m^2
    d) 4.900 kg m^2
    e) 0.2670 kg m^2
    No answer given yet