To solve this problem we will apply the first law of thermodynamics and we will make a balance between the heat transferred, its internal energy and the total work. Recall that for gases the definition of work can be expressed in terms of its pressure and volume. Let's start
Here,
dU = Internal Energy
dW = Work
But internal energy is unchanged, then
Where
= Change in Volume
P = Pressure
Finally, the expression of the heat transferred can be expressed in terms of pressure and volume, so it would end up becoming
Replacing,
Therefore the correct answer is B.
Nicholas Copernicus correctly assumed that the planets revolved around the sun but he incorrectly assumed that the planets followed a perfect circle orbit around the sun. It was later on discovered by Johannes Kepler that the planets moved around the sun following an elliptical orbit.
Answer:
a) 0.32 m b) -2.4 m c) 1.08 m/s d) -4 m/s
Explanation:
a)
- As the x and y axes (as chosen) are perpendicular each other, the movements along these axes are independent each other.
- This means that we can use the kinematic equations for displacements along both axes.
- In the x direction, as the only initial velocity is in the south direction (-y axis), the skateboarder is at rest, so we can write:
- In the y-direction, as no acceleration is acting on the skateboarder, we can write the following displacement equation:
- For t = 0.6s, replacing by the givens, we get the position (displacement from the origin) on the x-axis, as follows:
b)
- From (2) we can get the position on the y-axis (displacement from the origin) as follows:
c)
- In the x- direction, we can find the component of the velocity along this direction, as follows:
- Replacing by the values, we have:
d)
- As the skateboarder moves along the y-axis at a constant speed equal to her initial velocity, we have:
vfy = voy = -4 m/s
Answer:
t = 11.9 h = 0.49 day
Explanation:
First of all, we will find the area covered by the mower per unit time:
where,
v = speed of mower = 1 km/h = 1000 m/h
w = width of mower = 0.6 m
Therefore,
Now, the standard football ground has an area of:
A = 105 m x 68 m = 7140 m²
Therefore, The time required to mow the lawn will be:
<u>t = 11.9 h = 0.49 day</u>
Answer:
10 mm will be the answer my friend
