If you have 525 g of Iron how many moles of Iron do you have?

Adiver in midair has an angular velocity of 6.0 rad/s and a moment of inertia of 1.2 kg·m2. he then pulls is arms and legs into a tuck position and his angular velocity increases to 12 rad/s. the net external torque acting on the diver is zero. what is his moment of inertia in the tuck position?

Gordon is going for a run through the park, but it is cold outside. the low outside temperature could affect his personal safety.

What is the weight of a feather (mass = 0.0001 kg) that floats through earth's and the moon's atmospheres?