Answer:

Explanation:
h = Planck's constant = 
m = Mass of electron = 
k = Coulomb constant = 
e = Charge of electron = 
n = 1 (ground state)
Angular momentum is given by

From Bohr's atomic model we have


The centripetal force will balance the electrostatic force

The diameter is 
Answer:
The maximum height reached by the water is 117.55 m.
Explanation:
Given;
initial velocity of the water, u = 48 m/s
at maximum height the final velocity will be zero, v = 0
the water is going upwards, i.e in the negative direction of gravity, g = -9.8 m/s².
The maximum height reached by the water is calculated as follows;
v² = u² + 2gh
where;
h is the maximum height reached by the water
0 = u² + 2gh
0 = (48)² + ( 2 x -9.8 x h)
0 = 2304 - 19.6h
19.6h = 2304
h = 2304 / 19.6
h = 117.55 m
Therefore, the maximum height reached by the water is 117.55 m.
Answer:
a) 4.2m/s
b) 5.0m/s
Explanation:
This problem is solved using the principle of conservation of linear momentum which states that in a closed system of colliding bodies, the sum of the total momenta before collision is equal to the sum of the total momenta after collision.
The problem is also an illustration of elastic collision where there is no loss in kinetic energy.
Equation (1) is a mathematical representation of the the principle of conservation of linear momentum for two colliding bodies of masses
and
whose respective velocities before collision are
and
;

where
and
are their respective velocities after collision.
Given;

Note that
=0 because the second mass
was at rest before the collision.
Also, since the two masses are equal, we can say that
so that equation (1) is reduced as follows;

m cancels out of both sides of equation (2), and we obtain the following;

a) When
, we obtain the following by equation(3)

b) As
stops moving
, therefore,

Answer:28 m
Explanation:
Given
Direction is
North of east i.e.
with x axis
Also ball moved by 33 m
therefore its east component is 33cos58=17.48 m
Northward component 
Force = (mass) · (acceleration)
= (15 kg) · (8 m/s²)
= 120 kg-m/s² = 120 newtons