Answer:

Explanation:
Orbital velocity is the speed that a body that orbits around another body must have, for its orbit to be stable. For orbits with small eccentricity and when one of the masses is almost negligible compared to the other mass, like in this case, the orbital speed is given by:

Where M is the greater mass around which this negligible body is orbiting, r is the radius of the greater mass and G is the universal gravitational constant. So:

Answer:
Electric field on proton

Explanation:
Given that

We know that
Charge on proton

We know that
Force = Electric field x Charge
F= E x q



Electric field on proton

Answer:
the unit of work is derived unit because joule is defined the work done by the force aftab 1 newton causing the displacement of one metre something newton metre(n-m) is also used to measuring work.
Answer: The green house effect is best described by option 4 (Energy given off by earth is reflected off of earth's atmosphere back down to the surface).
Explanation:
The green house effect can be described as the energy given off by earth is reflected off of earth's atmosphere back down to the surface.
When energy from the sun passes through the atmosphere, some are absorbed which keeps the earth surface warm. While the rest is reflected back largely by cloud.
The energy which is emitted from the earth surface is called the infrared radiation. Some of the infrared radiation passess through the atmosphere but most is absorbed and re- emitted in all directions by the greenhouse gas molecules and clouds. This effect warms the earth surface and the lower atmosphere. Therefore this statement (Energy given off by earth is reflected off of earth's atmosphere back down to the surface) is correct about greenhouse effect.
For the greenhouse effect to occur, greenhouse gas molecules are mostly needed. Examples of these gases include:
--> Carbon dioxide (CO2),
--> Water vapor (H2O), and
--> Methane (CH4)
Over the years, the excessive human activities has lead to increase in the greenhouse gas molecules which has negatively affected the greenhouse effects.
Answer;
Amount of time the two substances are in contact
Area in contact between the two substances
Specific heat of the material that makes up the substances
Explanation;
The change in temperature of a substance is caused by heat energy. The change in temperature will depend on factors such as mass of the substance, the type of material it is made from, the time taken , specific heat of the material that makes the substance, and also the area of contact.
The amount of time the two substances are in contact affect the change in temperature such that if the two bodies are in contact for a longer time then a bigger change in temperature will be observed.
Specific heat capacity also determines the change in temperature that will be observed, such that a substance with a bigger specific heat capacity will record a small change in temperature.