Answer:
F= 67.5 N
Explanation:
We use the equation for the Coulomb's Law of Force between two charges Q1 and Q2 (in Coulombs) separated by a distance d (in meters):

where the constant k is the Coulomb's constant (
The charges are
, Q2=2.5*10^{-7}C; the distance we convert into meters to match the appropriate units of the Coulomb constant k (1 cm = 0.01 m)
Now we input all these data into the equation, knowing that given the appropriate units, the force will be expressed in Newtons (N):

Period of an ideal simple pendulum = 2π √(L / G)
1.87 = 2π √ (L / 9.81)
Divide each side by 2π : (1.87 / 2π) = √ (L / 9.81)
Square each side: (1.87 / 2π)² = L / 9.81
Multiply each side by 9.81 : L = (9.81) (1.87 / 2π)² = <em> 0.869 meter</em>
Choice 'D' is the closest one.
Answer:
ve = 8.06 x 10^5 m/s
vp = 1.882 x 10^4 m/s
Explanation:
K = 1.85 eV = 1.85 x 1.6 x 10^-19 J = 2.96 x 10^-19 J
me = 9.11 ✕ 10^-31 kg,
mp = 1.67 ✕ 10^-27 kg
Let the speed of electron is ve and the proton is vp.
For electron :
K = 1/2 me x ve^2
2.96 x 10^-19 = 0.5 x 9.11 x 10^-31 x ve^2
ve^2 = 6.498 x 10^11
ve = 8.06 x 10^5 m/s
For proton:
K = 1/2 mp x vp^2
2.96 x 10^-19 = 0.5 x 1.67 x 10^-27 x vp^2
vp^2 = 3.5449 x 10^8
vp = 1.882 x 10^4 m/s
The answer is 12.36. hoped this helped!
I believe it’s the mass of the box but I don’t no if I’m right
Hope this helped