Answer:
A. the satellite cools off by radiation.
Explanation:
First of all, let's define the three methods of heat transfer:
- Conduction: conduction occurs when two objects (or two substances) are in contact with each other - the heat is transferred by the warmer object to the colder object by collisions between the particles of the two objects
- Convection: convection occurs when a fluid is heated by an external source of heat - the heat transferred by the source produce a movement of the particles in the fluid (the warmer part becomes less dense and rises, being replaced by the colder part of fluid which sinks, producing a convective current)
- Radiation: radiation occurs when an object emits electromagnetic radiation, which carries energy and heat. Every object emits electromagnetic radiation, so every object emits heat by radiation.
While the first two methods (conduction and convection) occur only if there is a medium involved, radiation can also occur in a vacuum, so also in empty space. Therefore, the satellite in space cools off only by radiation, since conduction and convection are not possible.
Gravity (b) is the answer
Answer:
3.1 m/s
Explanation:
First, find the time it takes for the cat to land. Take down to be positive.
Given:
Δy = 0.61 m
v₀ = 0 m/s
a = 9.81 m/s²
Find: t
Δy = v₀ t + ½ at²
(0.61 m) = (0 m/s) t + ½ (9.81 m/s²) t²
t = 0.353 s
Now find the horizontal velocity needed to travel 1.1 m in that time.
Given:
Δx = 1.1 m
a = 0 m/s²
t = 0.353 s
Find: v₀
Δx = v₀ t + ½ at²
(1.1 m) = v₀ (0.353 s) + ½ (0 m/s²) (0.353 s)²
v₀ = 3.1 m/s
Answer:
A. In a closed system, the potential energy at the bottom is equal to the kinetic energy at the top.
Explanation:
According to the law of conservation of energy, energy is neither created nor destroyed but transformed from one form to another.
- Potential energy is the energy due to the position of a body
- Kinetic energy is the energy due to the motion of a body.
Based on the premise of the law of conservation of energy, both kinetic energy and potential energy are equal at the top and bottom in the system.
This way energy is conserved.