Answer:2 ft/s
Explanation:
Given
Length of Pole is 9 ft
Length of Joe is 3 ft
Joe walks away from Pole at the rate 4 ft/s
Let Joe is x m away from Pole so its shadow length is x'
From Similar triangle concept

3x'=x+x'
x=2x'
and it is given 
Differentiating



Because the object hovering over the magnet is the same magnetic pole.
The bigger the starting force, the further the distance moved by the car?
Answer: A. AB + C → AC + B
Explanation:
A single displacement reaction is also known as single replacement reaction. A reaction in which an element replaces another element from the compound is known as single displacement reaction.
AB + C → AC + B
Here, element C replaces another element B from compound AB.
Thus, option A represents is a general equation for a single displacement reaction
Option B represents a double displacement reaction where one element of a compound replaces another element of another compound and vice-versa, option C is a synthesis reaction where two reactants or more combine to form one product. Option D is a decomposition reaction in which multiple products are formed from a single reactant.
Answer:
E = 4.83 N/ C
Explanation:
If we have a uniform charge sphere we can use the following formulas to calculate the Electric field due to the charge of the sphere:
: Formula (1) To calculate the electric field in the region outside the sphere r ≥ a
Where:
K: coulomb constant (N*m²/C²)
a: sphere radius (m)
Q: Total sphere charge (C)
r : Distance from the center of the sphere to the region where the electric field is calculated (m)
Equivalences
1nC=10⁻⁹C
1cm= 10⁻²m
Data
k= 9*10⁹ N*m²/C²
Q=4nC=4 *10⁻⁹C
D = 26 cm = 26*10⁻²m = 0.26m
a = D/2 = 0.13m
r= R+a = 2.6 m+ 0.13m = 2.73m
Problem development
Magnitude of the electric field at r = 2.73m from the center of the sphere
r>a , We apply the Formula (1) :


E= 4.83 N/ C