Answer:
A. elements of the same kind with different numbers of neutrons
Explanation:
As we know that an atom is represented by

here we know that
z = atomic number
A = atomic number + number of neutrons
now if the number of neutrons in an atom is different but having same number atomic number then the combination of such group of atoms is known as isotopes.
So here we have

so above is the example of isotopes
Answer:
a) solar activity -- sudden eruptions of large bubbles of plasma and magnetic energy
and
d) solar flare -- sudden release of magnetic energy
Explanation:
We can start by eliminating the options that are definitely wrong.
A coronal mass ejection is not a relatively cool spot on surface of the sun, in fact such a spot is a sunspot, while a coronal mass ejection occurs when the magnetic field of the sun emerges as a loop. Thus, both options B and E are incorrect, leaving only A, C, and D. Option C makes no sense, as the sun's gravitational field does not 'churn'. Thus, only options A and D are left. A closer look at A and D reveals they are correct; solar flares are in fact sudden releases of magnetic energy, as seen in this quote from UC Berkeley's website; "Solar flares are caused by sudden changes of strong magnetic fields in the Sun's corona.". And solar activity is a blanket term for the effects of eruptions of plasma and magnetic energy from the sun.
<span>Answer: The acceleration of 10 kg object is greater than that of 18 kg object.
Explanation:
According to Newton's Second law:
F = ma --- (A)
Let's find the acceleration for both 10 kg and 18 kg objects!
The net force on both of these masses = F = 20N
(1) Acceleration of 10 kg object
Mass = m = 10 kg
Plug in the values in equation (A):
20 = 10 * a
Acceleration = a = 2 m/s^2
(2) Acceleration of 18 kg object
Mass = m = 18 kg
Plug in the values in equation (A):
20 = 18 * a
Acceleration = a = 1.11 m/s^2
2 > 1.11; therefore, 10 kg object has the higher acceleration compared to the acceleration of the 18 kg object.</span>
The kinetic energy K = 0.5 * m * v² must be equal to the potential energy U = m * g * h.
m mass
v velocity
h height
g = 9.81m/s²
The mass m cancels out:
0.5 * v² = g * h
Solve for height h and transform to distance traveled.
(sin (4°) = height / distance)
initially coin is at rest and then it drop for total time t = 1.5 s
so here the speed of the coin at which it will hit the floor is to be find

here we know that

a = 9.8 m/s^2
t = 1.5 s
now from above equation


so it will hit the floor with speed 14.7 m/s