Answer:
13.91 m/s
Explanation:
First we need to find the acceleration:
Acceleration = Force/mass
Acceleration = 36.7N/7.41 kg
Acceleration = 4.95 m/s² (rounded to two decimal places)
Then we find the velocity:
Velocity = Acceleration * Time
Velocity = 4.95 m/s² * 2.81 s
Velocity = 13.91 m/s (rounded to two decimal places)
Many devices have been invented to accurately measure temperature. It all started with the establishment of a temperature scale. This scale transformed the measurement of temperature into meaningful numbers.
In the early years of the eighteenth century, Gabriel Fahrenheit (1686-1736) created the Fahrenheit scale. He set the freezing point of water at 32 degrees and the boiling point at 212 degrees. These two points formed the anchors for his scale.
Later in that century, around 1743, Anders Celsius (1701-1744) invented the Celsius scale. Using the same anchor points, he determined the freezing temperature for water to be 0 degree and the boiling temperature 100 degrees. The Celsius scale is known as a Universal System Unit. It is used throughout science and in most countries.
There is a limit to how cold something can be. The Kelvin scale is designed to go to zero at this minimum temperature. The relationships between the different temperature scales are:
oK = 273.15 + oC oC = (5/9)*(oF-32) oF = (9/5)*oC+32
oF oC oK
Water boils 212 100 373
Room Temperature 72 23 296
Water Freezes 32 0 273
Absolute Zero -460 -273 0
At a temperature of Absolute Zero there is no motion and no heat. Absolute zero is where all atomic and molecular motion stops and is the lowest temperature possible. Absolute Zero occurs at 0 degrees Kelvin or -273.15 degrees Celsius or at -460 degrees Fahrenheit. All objects emit thermal energy or heat unless they have a temperature of absolute zero.
If we want to understand what temperature means on the molecular level, we should remember that temperature is the average energy of the molecules that composes a substance. The atoms and molecules in a substance do not always travel at the same speed. This means that there is a range of energy (the energy of motion) among the molecules. In a gas, for example, the molecules are traveling in random directions at a variety of speeds - some are fast and some are slow. Sometimes these molecules collide with each other. When this happens the higher speed molecule transfers some of its energy to the slower molecule causing the slower molecule to speed up and the faster molecule to slow down. If more energy is put into the system, the average speed of the molecules will increase and more thermal energy or heat will be produced. So, higher temperatures mean a substance has higher average molecular motion. We do not feel or detect a bunch of different temperatures for each molecule which has a different speed. What we measure as the temperature is always related to the average speed of the molecules in a system
Answer:
b) True Only if the finger is isolated from ground
c) True. The total charge does not change since the system is isolated
Explanation:
When the electroscope is touched with an acrylic rod, some charges are transferred from the electroscope to the rod, until the charge in both is equal.
In the case it know when the electroscope is touched with a finger, two things can happen.
- The body is isolated from the ground, the efective charge is redistributed between the two bodies. Case similar to insulating rod
- The body is connected to ground, the charge is transferred to the finger and from here to the ground until the total charge is transferred and the Earth and the final charge of the electroscope is zero.
Let's review the final statements
a) False, when part of the load is touched, it passes to the rod, so when it separates it does not return to the initial load
b) True Only if the finger is isolated from ground
c) True. The total load does not change since the system is isolated
d) False. The value of the load changes =, but its sign does not
Explanation:
By the second law of Newton we get the relation
F = ma
