Answer:
0.23348 A
Explanation:
B = Magnetic field
v = Velocity of electron = 
q = Charge of electron = 
= Vacuum permeability = 
r = Radius of circle = 0.026 m
N = Number of turns = 103 turns/cm = 
I = Current
The magnetic and centripetal force will be balanced

The magnetic field in solenoid is given by

From the first equation

The current in the solenoid is 0.23348 A
C.) Alpha Centauri
Explanation:
Due to it being the closest planetary system to earth.
About 4.367 light years away.
Speed = distance/time
= 400/72
=5.55 m/s
Answer:
The initial vertical velocity is zero, u = 0 m/s
Explanation:
Given;
height of the table, h = 0.55 m
horizontal distance traveled by the tennis, x = 0.12 m
Apply the following kinematic equation;
h = ut + ¹/₂gt²
where;
u is the initial vertical velocity = 0, since the tennis ball rolled off the edge of a table.
h = ¹/₂gt²
The time to fall from the vertical height is given by;

The initial horizontal velocity of the tennis is given by;
x = vₓt
vₓ = x / t
vₓ = (0.12) / (0.335)
vₓ = 0.358 m/s
Therefore, the initial vertical velocity is zero, u = 0 m/s and initial horizontal velocity, vₓ is 0.358 m/s
Answer: The smallest effort = 300N
Explanation:
Using one of the condition for the attainment of equilibrium:
Clockwise moment = anticlockwise moments
900 × 1 = 3 × M
Where M = the weight of the strong man
3M = 900
M = 900/3 = 300N
Therefore, 300N is the smallest effort that the strongman can use to lift the goat