Remember Newton's second law: F=ma
to get the force in newtons, mass should be in kg and acceleration in m/s^2
conveniently, we don't need to convert units
we just need to multiply the two to get the force
65* 0.3 = 19.5 kg m/s^2 or N
if significant digit is an issue, the least number if sig figs is 1 so the answer would be 20 N
Answer:

Explanation:
P = Power = 50 kW
n = Number of photons per second
h = Planck's constant = 
= Frequency = 781 kHz
r = Distance at which the photon intensity is i = 1 photon/m²
Power is given by

Photon intensity is given by

The distance is 
All of the above, work is a measurement of energy transfer, in Joules.
Potential energy = Joules
Kinetic energy = Joules
The key thing here is that anything having to do with just energy or energy transfer is measured in joules.
Answer:
(C). The line integral of the magnetic field around a closed loop
Explanation:
Faraday's law states that induced emf is directly proportional to the time rate of change of magnetic flux.
This can be written mathematically as;

is the rate of change of the magnetic flux through a surface bounded by the loop.
ΔФ = BA
where;
ΔФ is change in flux
B is the magnetic field
A is the area of the loop
Thus, according to Faraday's law of electric generators
∫BdL =
= EMF
Therefore, the line integral of the magnetic field around a closed loop is equal to the negative of the rate of change of the magnetic flux through the area enclosed by the loop.
The correct option is "C"
(C). The line integral of the magnetic field around a closed loop