Answer:
0.04973 W
Explanation:
I = Intensity of laser =
(assumed, as it is not given)
d = Diameter of spot = 1.31 mm
r = Radius = 
A = Area = 
Power is given by

The power output of the laser is 0.04973 W
The mass is moving by uniformly accelerated motion, with initial velocity

and acceleration

. Its position at time t is given by the following law:

where we take the initial position

since we are only interested in the distance traveled by the mass.
If we put

into the equation, the corresponding time t is the time it takes for the mass to travel this distance:


And the two solutions for the equation are:

--> negative, we can discard it

--> this is the solution to our problem
Answer:
Diameter of wire = 0.00021 meters
Explanation:
Given the following data;
Number of windings = 30
Length of windings = 6.3 mm to meters = 0.0063 meters
To find the diameter of the wire, we would use this mathematical expression;
Length of windings = number of windings * diameter of wire
Substituting the values into the expression, we have;
0.0063 = 30 * diameter of wire
Diameter of wire = 0.0063/30
Diameter of wire = 0.00021 meters
d through a railroad track