I think its 13...........
Answer:

Explanation:
Given data

To find
Magnitude of the net magnetic field B
Solution
The magnitude of the net magnetic field can be find as:

-- the big flash of light and heat coming out of the head
of a match when it gets hot enough;
-- the explosion of a tiny bit of gunpowder that can send
a bullet many miles;
-- the energy captured from a few drops of burning gasoline
that moves a car;
-- the energy in the carbohydrates you eat that is used
to move you around;
Answer:
66.5N
Explanation:
F = kx
Where F = force
K = spring constant
x = compression
Given
K = 950N/m
x = 7.0cm
F = ?
First convert the compression to meters .
7.0cm = 7.0 x 0.01
= 0.07 meters
Therefore
F = 950 x 0.07
= 66.5N
Answer:
The minimum speed of the box bottom of the incline so that it will reach the skier is 8.19 m/s.
Explanation:
It is given that,
Mass of the box, m = 2.2 kg
The box is inclined at an angle of 30 degrees
Vertical distance, d = 3.1 m
The coefficient of friction, 
Using the work energy theorem, the loss of kinetic energy is equal to the sum of gain in potential energy and the work done against friction.


W is the work done by the friction.







v = 8.19 m/s
So, the speed of the box is 8.19 m/s. Hence, this is the required solution.