You hold a 5-newton rock motionless in your hand. Regarding the forces on this rock,
A) the net force on the rock is zero.
B) the downward force of gravity is balanced by the upward force of air resistance.
C) there are no forces of any kind acting on the rock, because it is not moving.
D) the net force on the rock is 5 newtons, directed downward.
E) the net force on the rock is 5 newtons, directed upward.
A
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What is the distinguishing characteristic of what we call ordinary (or baryonic) matter?
A) It consists of atoms or ions with nuclei made from protons and neutrons. B) It emits a great deal of light. C) It can attract other matter through the force of gravity. D) It is made of subatomic particles that scientists call WIMPs.
A watch dial that continues to glow after a week in the dark is almost certainly
A) fluorescent. B) phosphorescent. C) polarized. D) radioactive.
Starting outside the region with the magnetic field, a single square coil of wire enters, moves across, and then leaves the region with a uniform magnetic field
perpendicular to the page so that the graph shown below represents the induced emf. The loop moves at constant velocity 
. As seen from above, a counterclockwise emf is regarded as positive. In which direction did the loop move over the plane of the page?
?
?
a.
The loop moved from bottom to top.
b.
The loop moved from top to bottom.
c.
The loop moved from left to right.
d.
The loop moved from right to left.
e.
All of these directions of motion will produce the graph of emf vs t.
A mass 
is connected by a light string that passes over a pulley of mass M to a mass 
as shown in the figure. Both masses move vertically and there is no slippage between the string and the pulley. The pulley has a radius of 30.0 cm and a moment of inertia of 
If 
is 4.00 kg, 
is 3.00 kg and M is 6.00 kg, then what is the acceleration of the masses?
A. 0.695 
B. 0.703
C. 0.731
D. 0.754
E. 0.805