So i believe is exercise:)
D because friction will slow it down going up hills (for safety reasons) and you go really fast going down.
Answer:
act or process of measuring
Explanation:
F = kq1q2/r^2
<span>q1 is first charge </span>
<span>q2 is second charge </span>
<span>k is 9 E9 </span>
<span>r is distance between them </span>
<span>F = (9E9)(2 E-6)(4 E-6)/2^2 = 0.018 N </span>
<span>A postive answer indicates a repulsive force</span>
Answer: 
Explanation:
The de Broglie wavelength
is given by the following formula:
(1)
Where:
is the Planck constant
is the momentum of the atom, which is given by:
(2)
Where:
is the mass of the electron
is the velocity of the electron
This means equation (2) can be written as:
(3)
Substituting (3) in (1):
(4)
Now, we only have to find
:
>>> This is the de Broglie wavelength of the electron