its D
i hope this helps to future test takers. i took the test and had to retake it because their wasn't an answer
Its option 3 an object has potential energy
Let k = the force constant of the spring (N/m).
The strain energy (SE) stored in the spring when it is compressed by a distance x=0.35 m is
SE = (1/2)*k*x²
= 0.5*(k N/m)*(0.35 m)²
= 0.06125k J
The KE (kinetic energy) of the sliding block is
KE = (1/2)*mass*velocity²
= 0.5*(1.8 kg)*(1.9 m/s)²
= 3.249 J
Assume that negligible energy is lost when KE is converted into SE.
Therefore
0.06125k = 3.249
k = 53.04 N/m
Answer: 53 N/m (nearest integer)
Answer:
114.92749 keV
Explanation:
r = Radius of trajectory
m = Mass of electron = 
B = Magnetic field = 0.044 T
q = Charge of electron = 
The centripetal force and the magnetic forces are conserved

Velocity of first electron

Velocity of second electron

Total kinetic energy is given by

Converting to eV


The energy of incident electron is 114.92749 keV
Mendeleev created a periodic table with 63 initial elements.
He left gaps for unknown elements.
To this date, there are 118 elements in the periodic table.