This is more to do with mathematics than physics,
but the square root of gravity on its own means nothing, its simply a acceleration due to gravity near the earth surface.
trying to find the speed of a falling object is a simple conservation of energy problem, then it has a meaning in that context.
however standing alone, it has no bearing to the real world. it is simply a mathematical term or construct we use in order to explain the real world. you see this all over the place in physics, you just have to get used to it.
for example:
mv^2=mhg
v^2=gh
v= SQRT(gh)
=SQRT(g)SQRT(h)
so SQRT means nothing on its own, simply a mathematical term to used to calculate the effects and actions in the real world.
i cant really compare it to Pi, sorry
but i hope you have a better understanding :)
Answer:
The change in the mechanical energy of the projectile is 43,750 J
Explanation:
Given;
mass of the projectile, m = 5 kg
initial velocity of the projectile, u = 200 m/s
final velocity of the projectile, v = 150 m/s
The change in mechanical energy is calculated from the principle of conservation of energy;
ΔP.E = ΔK.E
The change in potential energy is zero (0)
0 = ΔK.E
ΔK.E = K.E₁ - K.E₂
ΔK.E = ¹/₂mu² - ¹/₂mv²
ΔK.E = ¹/₂m(u² - v²)
ΔK.E = ¹/₂ x 5(200² - 150²)
ΔK.E = 43,750 J
Therefore, the change in the mechanical energy of the projectile is 43,750 J
Answer:
b. v = 0, a = 9.8 m/s² down.
Explanation:
Hi there!
The acceleration of gravity is always directed to the ground (down) and, near the surface of the earth, has a constant value of 9.8 m/s². Since the answer "b" is the only option with an acceleration of 9.8 m/s² directed downwards, that would solve the exercise. But why is the velocity zero at the highest point?
Let´s take a look at the height function:
h(t) = h0 + v0 · t + 1/2 g · t²
Where
h0 = initial height
v0 = initial velocity
t = time
g = acceleration due to gravity
Notice that the function is a negative parabola if we consider downward as negative (in that case "g" would be negative). Then, the function has a maximum (the highest point) at the vertex of the parabola. At the maximum point, the slope of the tangent line to the function is zero, because the tangent line is horizontal at a maximum point. The slope of the tangent line to the function is the rate of change of height with respect to time, i.e, the velocity. Then, the velocity is zero at the maximum height.
Another way to see it (without calculus):
When the ball is going up, the velocity vector points up and the velocity is positive. After reaching the maximum height, the velocity vector points down and is negative (the ball starts to fall). At the maximum height, the velocity vector changed its direction from positive to negative, then at that point, the velocity vector has to be zero.
A is the best answer. This is what makes the magnetic field of the magnet.
