Three blocks are shown: Block A
Block B
Block C
cm
11 cm
7 cm
13 cm
123cm
7 cm
7 cm
3 cm
1 cm
3 kg
4 kg
2 kg
Which statement is correct? (1 point)
a
Block A has the greatest density.
Block B has the greatest density
b
The density of Block A is equal to the density of Block B.
d
The density of Block B is equal to the density of Block C,

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

In the illustration, which two simple machines are being used to enable the student to reach the door? a. inclined plane and pulley b lever and wheel-and-axle c pulley and lever d wheel-and axle and inclined plane

Cyclotrons are widely used in nuclear medicine for producing short-lived radioactive isotopes. these cyclotrons typically accelerate h- (the hydride ion, which has one proton and two electrons) to an energy of 5 mev to 20 mev. this ion has a mass very close to that of a proton because the electron mass is negligible—about 1 2000 of the proton’s mass. a typical magnetic field in such cyclotrons is 1.9 t. (a) what is the speed of a 5.0-mev h-? (b) if the h- has energy 5.0 mev and b = 1.9 t, what is the radius of this ion’s circular orbit?