Answer:
6.4m/s
Explanation:
The total mechanical energy of the man is 1780J.
This mechanical energy is the energy due to the motion of the body and it is a form of kinetic energy.
Also, mass = 87kg
Kinetic energy = 
m v²
m is the mass
v is the velocity
1780 = x 87 x v²
v² = 40.9
v = 6.4m/s
<span>Is more than one displacement possible?
No, displacement only considers the initial and final position.
Is more than one average velocity possible?
No, the average velocity is defined as displacement per time and since there is only one displacement possible, there is only one average velocity possible as well.
Is more than one average speed possible?
Yes, the average speed considers the total distance traveled and this distance may not be the same as the total displacement.
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Answer:
c. density decreases because the molecules move farther apart
Explanation:
As a liquid is heated, the molecules move faster and move farther apart. This causes the volume to increase, which causes the density to decrease.
When acid reacts with water, the hydroxide ion is formed I think it is true.
A good electrical conductor is a material that has a lot of free charges that can easily move across the material, and with a large mean free path.
Now let's assume that one side of the material is at higher temperature than the other side. The charges on the hotter side move faster than the charges on the cooler side, so the faster charges transfer part of their energy to the charges of the cooler side by collisions. The larger the number of free charges (and the larger their mean free path), the faster is this transmission of energy (which is basically transmission of heat), so the larger is the thermal conductivity of the material, so a good electrical conductor is generally also a good thermal conductor.
