A student holds two lead weights, each of mass 7.4 kg. When the students’ arms are extended
horizontally, the lead weights are 1.1 m from
the axis of rotation and the student rotates
with an angular speed of 2.1 rad/sec. The
moment of inertia of student plus stool is
6.9 kg m2
and is assumed to be constant; i. e.,
the student’s arms are massless! Then the
student pulls the lead weights horizontally to
a radius 0.19 m from the axis of rotation. Calculate the final angular speed of the
system.
Answer in units of rad/s.

Brutus, the dog, is pulling a bone to the left with a force of 20 n. lassie, another dog, is pulling a bone to the right with a force of 18n. what is the net force? a. b. c.

What does si stand for, when referring to a system of measurement

1. what is the relationship between wavelength and the penetrating power of an electromagnetic wave? a) the penetrating power has no relationship to the wavelength. b) the penetrating power increases as the wavelength increases. c) the penetrating power decreases as the wavelength increases. d) the penetrating power decreases as the wavelength decreases. 2. as ice melts and turns into water, the speed of sound through the material would most likely do what? justify your answer. a) the speed would not change because the material is always water. b) the speed of sound would increase because the density of water is less than that of ice. c) the speed of sound would increase because energy is added to ice in order to make it melt. d) the speed of sound would decrease because sound travels faster through solids than liquids. 3.which of these waves need a medium to travel through? a) sound b) x-rays c) infrared rays d) visible light