Answer:
Lindsey biked 45 miles for 3 hours at 15 mph and walked 8 miles for 2 hours at 4 mph.
Explanation:
Speed = distance/time
Let the distance that Lindsey biked through be x miles and the time it took her to bike through that distance be t hours
Then, the rest of the distance that she walked is (53 - x) miles
And the time she spent walking that distance = (5 - t) hours
Her biking speed = 15 mph = 15 miles/hour
Speed = distance/time
15 = x/t
x = 15 t (eqn 1)
Her walking speed = 4 mph = 4 miles/hour
4 = (53 - x)/(5 - t)
53 - x = 4 (5 - t)
53 - x = 20 - 4t (eqn 2)
Substitute for X in (eqn 2)
53 - 15t = 20 - 4t
15t - 4t = 53 - 20
11t = 33
t = 3 hours
x = 15t = 15 × 3 = 45 miles.
(53 - x) = 53 - 45 = 8 miles
(5 - t) = 5 - 3 = 2 hours
So, it becomes evident that Lindsey biked 45 miles for 3 hours at 15 mph and walked 8 miles for 2 hours at 4 mph.
The first model of the atom was developed by JJ Thomson in 1904, who thought that atoms were composed purely of negatively charged electrons. This model was known as the 'plum pudding' model.
This theory was then disproved by Ernest Rutherford and the gold foil experiment in 1911, where Rutherford shot alpha particles at gold foil, and noticed that some went through and some bounced back, implying the existence of a positive nucleus.
In 1913, Niels Bohr proposed a model of the atom where the electrons were contained within quantized shells that orbited the nucleus. This was because it was impossible for the cloud of negative electrons proposed by Rutherford to exist, as the negative electrons would be drawn to the positive nucleus, and the atom would collapse in on itself.
In 1926, the Austrian physicist Erwin Schrödinger created a quantum mechanical model of the atom by combining the equations for the behavior of waves with the de Broglie equation to generate a mathematical model for the distribution of electrons in an atom.
However the model used today is closest to the Bohr model of the atom, using the quantized shells to contain the electrons.
For more info:
http://chemistry.about.com/od/chemistryglossary/a/debroglieeqdef.htm
The correct answer is
D. Groups and Families
I did the quiz nd this was the right answer
Hopes this helps :)
Answer:
Impedance = 93.75 ohms
Current = 1.81 A
Explanation:
Resistance = R = 80 ohms
Inductance = L = 0.2 H
Inductive reactance = XL = 
= ωL = (2πf) L
= 2 (3.14) (60)(0.2) = 75.398 Ohms
Capacitive reactance = 1 / ωC = 1/(2πf)C = 1 / [(2π)(60)(0.1 × 10⁻3)]
= 26.526 Ohms
Impedance = Z = 
= 
= 93.747 ohms
Voltage = 
× 120 = 169.7056 V
Current = I = V ÷ R = (169.7056) ÷ 93,747 = 1.81 A
This
B: False, because the definition
is lacking.
Force
is when two objects interact with one another causing it to either move or not
move. In our daily lives there are a lot of times force is exerted upon us,
rather force is everywhere and here are the evidences:
*Pushing
a cart
*Pushing
a wall
*Hitting
a baseball bat
*Apple
falling down from a tree.
*Balls
hitting one another
*A
swinging pendulum
*Throwing
a paper with stone above it
*Breaking
of glass in the floor
*Falling
of leaves on the grass
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