B. Extra text to get to 20 characters.
Answer:
The correct answer is All of the above.
Explanation:
The answer is 60 mph.
The speed (v) is distance (d) per time (t): v = d/t
Car A:
v1 = ?
t1 = 2 h
d1 = ?
___
v1 = d1/t1
d1 = v1 * t1
Car B:
v2 = ?
t2 = 1.5 h
d2 = ?
___
v2 = d2/t2
d2 = v2 * t2
<span>Two cars traveled equal distances:
d1 = d2
</span>v1 * t1 = v2 * t2
<span>Car B traveled 15 mph faster than Car A:
v2 = v1 + 15
</span>v1 * t1 = v2 * t2
v2 = v1 + 15
________
v1 * 2 = (v1 + 15) * 1.5
2v1 = 1.5v1 + 22.5
2v1 - 1.5v1 = 22.5
0.5v1 = 22.5
v1 = 22.5/0.5
v1 = 45 mph
v2 = v1 + 15
v2 = 45 + 15
v2 = 60 mph
Answer:
The current of the solenoid is 0.0129 A.
Explanation:
The movement of the electron within the solenoid in a circle is produced by equaling the magnetic force and the centripetal force, as follows:


Where:
I: is the current
m: is the electron's mass = 9.1x10⁺³¹ kg
v: is the electron's speed = 3.0x10⁵ m/s
μ₀: is the permeability magnetic = 4πx10⁻⁷ T.m/A
n: is the number of turns per unit length = 35/cm
r: is the radius of the circle = 3.0 cm
e: is the electron's charge = 1.6x10⁻¹⁹ C
Therefore, the current of the solenoid is 0.0129 A.
I hope it helps you!