Answer:
The stars are moving away from us.
Explanation:
The observed wavelengths of hydrogen transition for stars A and B (660.0 nm and 666 nm respectively) are greater than that observed in the laboratory (656.2 nm). The observed long wavelengths for the stars means that the light from the stars is red-shifted.
According to the Doppler effect, red-shifted light means that the source is moving a way from the observer; therefore, we arrive at the conclusion that the stars A and B are moving away from us.
The roadway with the highest number of hazards is <span>city streets</span>
Answer:
7350 J
Explanation:
The gravitational potential energy of the rock sitting on the edge of the cliff is given by:

where
m is the mass of the rock
g is the gravitational acceleration
h is the height of the cliff
In this problem, we have
m = 50 kg
g = 9.8 m/s^2
h = 15 m
Substituting numbers into the formula, we find:

Answer:
v=8m/s
Explanation:
To solve this problem we have to take into account, that the work done by the friction force, after the collision must equal the kinetic energy of both two cars just after the collision. Hence we have
![W_{f}=E_{k}\\W_{f}=\mu N=\mu(m_1+m_1)g\\E_{k}=\frac{1}{2}[m_1+m_2]v^2](https://tex.z-dn.net/?f=W_%7Bf%7D%3DE_%7Bk%7D%5C%5CW_%7Bf%7D%3D%5Cmu%20N%3D%5Cmu%28m_1%2Bm_1%29g%5C%5CE_%7Bk%7D%3D%5Cfrac%7B1%7D%7B2%7D%5Bm_1%2Bm_2%5Dv%5E2)
where
mu: coefficient of kinetic friction
g: gravitational acceleration
We can calculate the speed of the cars after the collision by using

Now , we can compute the speed of the second car by taking into account the conservation of the momentum

the car did not exceed the speed limit
Hope this helps!!
1) 
When both the electric field and the magnetic field are acting on the electron normal to the beam and normal to each other, the electric force and the magnetic force on the electron have opposite directions: in order to produce no deflection on the electron beam, the two forces must be equal in magnitude

where
q is the electron charge
E is the magnitude of the electric field
v is the electron speed
B is the magnitude of the magnetic field
Solving the formula for v, we find

2) 4.1 mm
When the electric field is removed, only the magnetic force acts on the electron, providing the centripetal force that keeps the electron in a circular path:

where m is the mass of the electron and r is the radius of the trajectory. Solving the formula for r, we find

3) 
The speed of the electron in the circular trajectory is equal to the ratio between the circumference of the orbit,
, and the period, T:

Solving the equation for T and using the results found in 1) and 2), we find the period of the orbit:
