Answer:
35 kilogram per stair will weight
I believe it is the nervous system.
Answer:
d. W<0 and Q<0
Explanation:
Heat (Q) and work (W) are ways of exchange of energy.
When a system gains heat, that its temperature increases, and, because the heat flows to the system it's positive (Q>0), and when it loses heat the inverse happens and Q<0.
When the system expands, it does work at the surroundings, so the work is going from the system, and it's positive (W >0), when the inverse happens, the work goes to the system and W<0.
So, the gas is compressed, then W<0, and it warms up. To cold it, the tank has put a tub with water, do the gas will lose heat and Q<0.
For the mass m, attached to a spring, to move in a circle centripetal force and restoring force of the spring must be equal. Centripetal force is given with this formula:
Restoring force only occurs if the spring is stretched. If L is the length of unstretched spring we have the following formula for restoring force:
r is the length of a circle that mass m is traveling along.
As said above, these two forces have to be equal:
We solve for r:
r(w) will go to infinity when denominator is equal to zero:
Please keep in mind that Hooke's law has it's limitations, and before we reach our critial value of angular velocity spring will be strecthed to a point where Hooke's law does not aply anymore.
Density of a material depends upon it's mass & volume.
You can calculate it by: Density = Mass / Volume
Hope this helps!