The Correct answer to this question for Penn Foster Students is: 214.4 J
Explanation:
Given that,
Initial speed of the billiard ball 1, u = 30i cm/s
Initial speed of another billiard ball 2, u' = 40j cm/s
After the collision,
Final speed of first ball, v = 50 cm/s
Final speed of second ball, v' = 0 (as it stops)
Let us consider that both balls have same mass i.e. m
Initial kinetic energy of the system is :

Final kinetic energy of the system is :

The change in kinetic energy of the system is equal to the difference of final and initial kinetic energy as :
So, the change in kinetic energy of the system as a result of the collision is equal to 0.
Answer:
B = 0.07 mT
Explanation:
q = 1.6x10^-19 coulombs
for the electron to pass through the field undeflected the magnetic force acting on it must equal the electrical force due to the electric field
electric force = Eq = 16000 * 1.6x10^-19 newtons
magnetic force = qvB = 1.6x10^-19 * 2.7x10^8 * B
16000 * 1.6x10^-19 = 1.6x10^-19 * 2.7x10^8 * B
B = 0.07 mT (milli tesla)