you are so wise how do you do it?
Hooke's law states that for a helical spring the extension is directly proportional to the force applied provided the elastic limit is not exceeded.
Therefore; F= ke, where k is the spring constant, F is the force and e is the extension.
k = 2700 N/m and e = 3 cm or 0.03 M
therefore, F = 2700 × 0.03
= 81 N
Thus, the force required will be 81 N
Answer:
E. All of the above.
Explanation:
These are the equations for potential (PE) and kinetic energy (KE):
PE = m · g · h
Where:
m = mass of the object.
g = acceleration due to gravity.
h = height.
KE = 1/2 · m · v²
Where:
m = mass.
v = speed.
At the end points of its swings, the pendulum is at its maximum height and its velocity is zero (for an instant). Then all the energy at these points is potential (answer B).
As the pendulum swings back from the end point it starts to lose height and acquires kinetic energy until it reaches the lowest part of the of its swing. At this point, all the potential energy was transformed into kinetic energy. The potential energy will be zero (because the height is zero) and due to energy conservation, the energy that once was potential energy has to be transformed into some kind of energy, in this case, into kinetic energy (we assume there is no air resistance, in which case some energy would be transformed into thermal energy as well, i.e., heat). (answer A and D).
After the lowest point, the pendulum acquires height (potential energy increases) and, due to the acceleration of gravity, it starts to lose velocity (kinetic energy decreases). Due to conservation of energy, the increase in potential energy must be equal to the decrease in kinetic energy. The kinetic energy is transformed into potential energy (answer C).
Then, the answer is E. All answers are correct.
Answer:
The statement about atmospheric pressure that is false is <u><em>option d) With an increase in altitude, atmospheric pressure increases as well. </em></u>
Explanation:
Atmospheric pressure as the force exerted by atmospheric air on the earth's surface. The higher the height of the earth's surface with respect to sea level, which is the reference point, the lower the air pressure. In other words, atmospheric pressure decreases in altitude. This is because, the higher the height, the smaller the amount of air present for pressure. For example, on a mountain the amount of air in the highest part is less than that on a beach. This means that there is lower atmospheric pressure at the top.
Although it must be taken into account that the atmospheric pressure does not decrease proportionally in height, due to the high compressibility of the fluid (gas).
At sea level, which is the reference point, atmospheric pressure takes a value in different units of 1 atmosphere, 1013 millibars or 760 mm Hg.
So, <u><em>the statement about atmospheric pressure that is false is option d) With an increase in altitude, atmospheric pressure increases as well.</em></u> This is because, as mentioned, with an increase in altitude, the atmospheric pressure decreases.
