Answer:
In a velocity selector, there are two forces namely;
» Electric field Intensity
» Magnetic field density
<u>Relationship</u><u>:</u>

E is the electric field intensity
B is the magnetic flux density
Answer:
Friction always acts opposite to the motion.
<h3><u>Answer;</u></h3>
Satellite
Differences in ocean-surface height can be measured by<u> Satellite</u>
<h3><u>Explanation;</u></h3>
- The topography of the ocean or the height of the ocean surface relative to a level of no motion provides the information on tides, and the distribution of heat and mass in the Earths's oceans.
- <em><u>The ocean topography is measured using satellites altimeter. Satellites use radar altimeters that are specially made to measure the height of the ocean surface. The satellites measure the height of the ocean surface with an accuracy of 3 cm relative to the center of the earth.</u></em>
- Satellite altimeter combines precise orbit determination with accurate ranging by a microwave altimeter of ocean distance to the satellite.
The potential energy of any object depends on its mass as well as its height off the ground.
Potential energy = mass x gravity x height.
We don't have enough information to compare the potential energies of these two objects because we don't know their masses.