Answer:
Explanation:
height of pole = 15 ft
height of man = 6 ft
Let the length of shadow is y .
According to the diagram
Let at any time the distance of man is x.
The two triangles are similar

15 y - 15 x = 6 y
9 y = 15 x

Differentiate with respect to time.

As given, dx/dt = 4 ft/s

ft/s
Answer:

Explanation:
Firstly, when you measure the voltage across the battery, you get the emf,
E = 13.0 V
In order to proceed we have to assume that the voltmeter offers no loading effect, which is a valid assumption since it has a very high resistance.
Secondly, the wires must be uniform. So the resistance per unit length is constant (say z). Now, even though the ammeter has very little resistance it cannot be ignored as it must be of comparable value/magnitude when compared to the wires. This is can seen in the two cases when currents were measured. Following Ohm's law and the resistance of a length of wire being proportional to it's length, we should have gotten half the current when measuring with the 40 m wire with respect to the 20 m wire (
). But this is not the case.
Let the resistance of the ammeter be r
Hence, using Ohm's law we get the following 2 equations:
.......(1)
......(2)
Substituting the value of r from (2) in (1), we have,

which simplifying gives us,
(which is our required solution)
putting the value of z in either (1) or (2) gives us, r = 0.5325 
Your gas mileage would be 22.93 miles per gallon.
Answer:
500 kg
Explanation:
using the formula Potential energy (p.e)=mgh where g= acceleration due to gravity whose value is 9.8
so,pe =mgh
622300=m*9.8*127
m=500kg
Answer:
There is an arrow up for air resistance and an arrow down for gravity. The arrow up is longer than the arrow down.
Explanation:
The text of the problem says that the skydiver is slowing down: this means that he has an acceleration, which is directed opposite to the motion of the skydiver. Since the motion is downward, the acceleration must be upward.
There are two forces acting on the skydiver: the gravity (downward) and the air resistance (upward). According to Newton's second law:
F=ma
the acceleration has the same direction of the net force, so the net force must also be upward: therefore, the air resistance must be greater than the gravity, so the arrow up for air resistance is longer than the arrow down for gravity.