Answer:
The correct option is A
Explanation:
Firstly, it should be noted that the freezing point of a substance can be assumed to be melting point of that substance because a substance will normally change from liquid to solid (freezes) at the same point it changes from solid to liquid (melts). For example, water freezes at 0°C and also starts melting at 0°C.
Thus, the substance with the lowest melting point among the substances mentioned in the question is alcohol (ethanol) with the melting point of -114°C. Hence, <u>ethanol also has the lowest freezing point thereby freezing at the lowest temperature.</u>
AnswerIt is continuously falling towards the surface of the earth
Explanation:
since gravity from earth is the thing that keeps it constantly in orbit
The Kinetic energy of an object is given by:
Where m is the mass of the object (kg) and v is the velocity of the object (ms-1)
Substituting in:
Therefore the Kinetic energy of the object is
1.35MJ
Answer:
Explanation:
Given that,
Hot temperature
T_H = 96°F
From Fahrenheit to kelvin
°K = (°F - 32) × 5/9 + 273
°K = (96 - 32) × 5/9 + 273
K = 64 × 5/9 + 273 = 35.56 + 273
K = 308.56 K
T_H = 308.56 K
Low temperature
T_L = 70°F
Same procedure to Levine
T_L = (70-32) × 5/9 + 273
T_L = 294.11 K
A carnot refrigerator working between a hot reservoir and at temperature T_H and a cold reservoir and at temperature T_L has a coefficient of performance K given by
K = T_L / (T_H - T_L)
K = 294.11 / (308.56 - 294.11)
K = 294.11 / 14.45
K = 20.36
Then, the coefficient of performance is the energy Q_L drawn from the cold reservoir as heat divided by work done,
So, for each joules W = 1J
K = Q_L / W
Then,
Q_L = K•W
Q_L = 20.36 × 1
Q_L = 20.36 J
Q_L ≈ 20J
So, approximately 20J of heats are removed from the room
Answer:
Explanation:
The force needed to pull up the backpack up increases as the backpack gets higher because the force of gravity needs to be encountered by the tension of the string. According to the formula to calculate the tension, assuming both are equal 
, the force of tension increases as the angle(with respect to horizontal axis) decreases. It is not possible to pull the rope hard enough because there will be no force in the y direction to counter the Fg; therefore, infinite force is needed.
