Answer:
A
Explanation:
If the object is moving at a constant speed, the object isn't accelerating as the velocity doesn't change.
Answer:
The average speed for the entire run is 12 km/h.
Explanation:
The average speed is given by the following equation:

Where:
: is the total distance
: is the total time
If during the first hour, they ran a total of 13 kilometers and then, they ran 5.0 kilometers during the next half an hour we have:


Hence, the average speed is:

Therefore, the average speed for the entire run is 12 km/h.
I hope it helps you!
Answer:
Explanation:
The classification will be made into 3 categories, which are
Ones that shortens wavelengths
Ones that lengthens wavelengths
Ones that has no effect on wavelengths
Shortens wavelengths -> Increase frequency
Lengthens wavelengths -> Decrease frequency
No effect -> Increase amplitude, decrease amplitude, increase damping, decrease damping.
Answer:
Ea = 112500[J]
Eb = 87500[J]
Explanation:
To solve this problem we must use the principle of energy conservation which tells us that the energy of a body plus the work done or applied by the body equals the final energy of a body.
This can be easily visualized by the following equation:

Now we must define the energies at points A & B.
<u>For point A</u>
At point A we only have kinetic energy since it moves at 15 [m/s]
So the kinetic energy
![E_{A}=\frac{1}{2}*m*v_{A}^{2} \\E_{A}=\frac{1}{2} *1000*(15)^{2} \\E_{A}=112500[J]](https://tex.z-dn.net/?f=E_%7BA%7D%3D%5Cfrac%7B1%7D%7B2%7D%2Am%2Av_%7BA%7D%5E%7B2%7D%20%20%5C%5CE_%7BA%7D%3D%5Cfrac%7B1%7D%7B2%7D%20%2A1000%2A%2815%29%5E%7B2%7D%20%5C%5CE_%7BA%7D%3D112500%5BJ%5D)
The final kinetic energy can be calculated as follows:
![112500-25000=E_{B}\\E_{B}=87500[J]](https://tex.z-dn.net/?f=112500-25000%3DE_%7BB%7D%5C%5CE_%7BB%7D%3D87500%5BJ%5D)