15) a
16) b
17) a
Hope this helps
By definition, we have to:
Newton's first law states that any object will remain in a state of rest or with a uniform rectilinear motion unless an external force acts on it.
Therefore, according to the first law of Newton, if the object is already in motion and has no force acting on it then, it will remain with a uniform rectilinear motion.
Answer:
The object will remain with a uniform rectilinear movement when the external force does not act on it.
Answer:
n = 4 x 10¹⁸ photons
Explanation:
First, we will calculate the energy of one photon in the radiation:

where,
E = Energy of one photon = ?
h = Plank's Constant = 6.625 x 10⁻³⁴ J.s
c = speed of light = 3 x 10⁸ m/s
λ = wavelength of radiation = 567 nm = 5.67 x 10⁻⁷ m
Therefore,

E = 3.505 x 10⁻¹⁹ J
Now, the number of photons to make up the total energy can be calculated as follows:

<u>n = 4 x 10¹⁸ photons</u>
8 because of the amount of calcium in the equator of the state Minnesota