Answer:
Qh = -491.85J
(It is negative due to rejected heat)
Explanation:
In the question, the heat received by the refrigerator is at the cold reservoir where Qc= 415J
Now, we are looking for Qh.
Thus, using thermodynamics equation, we have;
Qc/Qh = — Tc/Th
Making Qh the subject, we obtain ;
-(QcTh)/Tc = Qh
Plugging in the relevant values, we obtain ;
-(415x320)/270 = - 132800/270 =
- 491.85J
D is the correct answer, assuming that this is the special case of classical kinematics at constant acceleration. You can use the equation V = Vo + at, where Vo is the initial velocity, V is the final velocity, and t is the time elapsed. In D, all three of these values are given, so you simply solve for a, the acceleration.
A and C are clearly incorrect, as mass and force (in terms of projectile motion) have no effect on an object's motion. B is incorrect because it is not useful to know the position or distance traveled, unless it will help you find displacement. Even then, you would not have enough information to use a kinematics equation to find a.
Answer:
option the correct is B
Explanation:
Let's analyze the different options, for a closed system
- an internal reaction changes the system, but does not affect the surrounding environment
- Heat, is a means of transfer that occurs when two bodies are in contact, one of the body can be a closed system since the only thing that happens is thermal transfer, without movement of the system itself. This is the correct result.
- Work implies a movement whereby the system must be mobile, it is not an option
- Pressure change. change in the system, but does not affect the environment
- Mass transfer is not possible in a closed system
After analyzing each option the correct one in B
Answer:
11121.19 kg
Explanation:
Given that,
the gravitational force between Earth and the telescope is ![9.21\times 10^4\ N](https://tex.z-dn.net/?f=9.21%5Ctimes%2010%5E4%5C%20N)
Mass of the Earth is ![5.98\times 10^{24}\ kg](https://tex.z-dn.net/?f=5.98%5Ctimes%2010%5E%7B24%7D%5C%20kg)
The center of the Hubble space telescope is 6940 km from Earth’s center.
We know that, the force of gravity is given by the formula as follows :
![F=\dfrac{GmM}{r^2}](https://tex.z-dn.net/?f=F%3D%5Cdfrac%7BGmM%7D%7Br%5E2%7D)
m is mass of telescope and M is mass of Earth
So,
![m=\dfrac{Fr^2}{GM}\\\\m=\dfrac{9.21\times 10^4\times (6940\times 10^3)^2}{6.67\times 10^{-11}\times 5.98\times 10^{24}}\\\\m=11121.19\ kg](https://tex.z-dn.net/?f=m%3D%5Cdfrac%7BFr%5E2%7D%7BGM%7D%5C%5C%5C%5Cm%3D%5Cdfrac%7B9.21%5Ctimes%2010%5E4%5Ctimes%20%286940%5Ctimes%2010%5E3%29%5E2%7D%7B6.67%5Ctimes%2010%5E%7B-11%7D%5Ctimes%205.98%5Ctimes%2010%5E%7B24%7D%7D%5C%5C%5C%5Cm%3D11121.19%5C%20kg)
So, the mass off the telescope is 11121.19 kg
The charge of one electron is
![e=1.6 \cdot 10^{-19}C](https://tex.z-dn.net/?f=e%3D1.6%20%5Ccdot%2010%5E%7B-19%7DC)
. In order to have 1 C of charge, we need to have N electrons such that their total charge is 1 C:
![1 C = Ne](https://tex.z-dn.net/?f=1%20C%20%3D%20Ne)
By rearranging the equation, we can easily calculate the number of electrons contained in 1 C of charge: