Explanation:
C.
Object A will require more force to be set in motion but will travel faster than object B.
2. true
Answer:
Air resistance slows down the ball
In space, there would be no air resistance
Explanation:
When an object moves through the air, there is a force acting in the opposite direction to the motion of the ball: this force is called air resistance.
Air resistance is due to the friction between the molecules of air and the molecules at the surface of the object - because of this frictional force, the object is slows down in its motion and loses some energy (which is converted into thermal energy of the surrounding air).
There is also the force of gravity (downward) that acts on the ball: however, this force does not slows down the ball in its motion, instead it accelerates it towards the ground.
In space, however, there is no air and no gravity. This means that there are no forces acting on the ball: therefore, the ball will not be slowed down, and therefore will continue its motion forever, at constant velocity, according to Newton's first law:
<em>An object at rest (or in motion) will stay at rest (or in motion at constant velocity) when the net external force acting on it is zero</em>
Answer:
Theory
Explanation:
Conservation of energy is explained as a scientific law and not a theory because it does not explain why energy is conserved.
A law is a the statement of a scientific fact. It is a product of repeated experiment and observation through time. Most laws do not explain the reason for the logic behind their premise.
A theory on the other hand provides an explanation for an observed phenomenon. Most theories are no immutable. They are often changed when new finds are reported or made.
Laws are immutable and they stand still.
Answer:
The correct option is;
(c) 64W
Explanation:
Here we have the Coefficient Of Performance, COP given by
The heat change from 23° to 6°C for a mass of 10 kg/h which is equivalent to 10/(60×60) kg/s or 2.78 g/s we have
= m·c·ΔT = 2.78 × 4.18 × (23 - 6) = 197.39 J
Therefore, plugging in the value for in the COP equation we get;
which gives
Since we were working with mass flow rate then the power input is the same as the work done per second and the power input to the refrigerator = 63.674 J/s ≈ 64 W.
The power input to the refrigerator is approximately 64 W.
Answer:
A calorie is defined as the amount of energy needed to raise the temperature of one gram of water one degree Celsius.
Explanation:
The other unit used to measure heat is the joule. The joule is the SI (System International) unit
