Jenny and Alyssa are members of the cross-country team. On a training run, Jenny starts off and runs at a con-stant 3.8 m/s. Aly
1 answer:
Answer:Answer:
300 seconds
Explanation:
We solve this problem using the equation of uniform motion;
d =v*t
d: Distance traveled
t: Time
v: Speed
We raise the equations of uniform motion because they run at a constant speed.
dJ=3.8*tJ Motion equation for Jenny
dA=4*tA Motion equation for Alyssa
d:distancia
When Jenny and Alissa meet, they will have traveled the same distance,then:
dJ=dA
3.8 tJ =4*tA
tA = * tJ
tA =0.95¨*tJ Equation (1)
Jenny runs 15 seconds longer than Alyssa,then:
tJ = tA+15 Equation (2)
We replace tA =0.95tJ of the Equation (1) in the Equation (2):
tJ = 0.95*tJ +15
tJ-0.95*tJ=15
0.05* tJ=15
tJ=
tJ=300 s
Alyssa catch up with Jenny in 300 s after Jenny’s start .
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A) Order of the first laser: 3, order of the second laser: 2
B) The overlap occurs at an angle of
Explanation:
A)
The formula that gives the position of the maxima (bright fringes) for a diffraction grating is
where
d is spacing between the lines in the grating
is the angle of the maximum
m is the order of diffraction
is the wavelength of the light
For laser 1,
For laser 2,
where
Since the position of the maxima in the two cases overlaps, then the term on the left is the same for the two cases, therefore we can write:
Therefore:
B)
In order to find the angle at which the overlap occurs, we use the 1st laser situation:
where:
N = 450 lines/mm = 450,000 lines/m is the number of lines per unit length, so the spacing between the lines is
is the order of the maximum
is the wavelength of the laser light
Solving for , we find the angle of the maximum:
So the angle is
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Explanation:
If we assume that the Earth is a spherical conductor, according to Gauss's Law, the electric field is given by:
Here k is the Coulomb constant, the excess charge on the Earth's surface and r its radius. Solving for q: