Answer:
there is no change because a physical change only changes the physical appearance of a substance
Explanation:
a chemical change is the only change that can change a substance since it changes the chemical properties of the substance, hence making a new substance
Answer:
When Copernicus first systematically created his Sun-centered model of the universe, it did not lead to substantially better predictions of planetary positions than the Ptolemaic model because the Catholic Church, which was the power at the time, stated it was false, and anybody who believed Copernicus and spread the "myth" were excommunicated or even executed. This was because a sun centered universe would mean that everything the Catholic Church had been teaching about how the Earth was the center of the universe would be false. If people believed it, the church would no longer be seen as the infallible authority, so they needed to stop it from spreading.
Answer: B=1.92nT
Explanation:This question uses the Biot-Savart law: the law is an equation that describes the magnetic field created by a current-carrying wire, and allows you to calculate its strength at various points.
B=(μ0/4*π)*q*v*r(unit vector)/r²
Also:
B=(μ0/4*π)*q*v*sin(θ)/r²
Where;
μ0 =permeability of free space = 4πx10-7 Hm-1
B = magnetic field in Tesla
V= velocity
r= radius
Therefore:
B=(4πx10-7/4*π)*q*v*sin(θ)/r^2
B=1x10-7*q*v*sin(θ)/r^2
Using:
q=15x10-3C
v=40m/s
tan(θ)=5/2 so θ=68.2°
r²=5²+2² (Pythagoras Theorem)
B can be calculated as:
B=1x10-7*15x10-3*40*sin(68.2)/(5²+2²)
B=1.92nT
If i could heat a piece of iron so that it melted, and then held a magnet close to the molten iron and then let the iron cool to room temperature, you could use a microscope to look at the iron and tell that a magnet had been present during cooling. you could even tell if it was the north or south pole of the magnet that i held close to the molten iron.
Magma/lava contains a lot of molten iron so that when it erupts from a volcano and cools, the magnetic field of the earth leaves an imprint in it, just like the cooling iron from above. From this imprint we can tell the strength of the magnetic field and also which direction the north and south poles were at the time.
Answer:
(a) -8064 N
(b) 8064 N
Explanation:
(a)
From Newton’s law of motion, Force, F=ma where m is mass and a is acceleration.
Since acceleration is the rate of change of velocity per unit time, then where v is velocity and the subscripts f and I denote final and initial
For the first ball, the mass is 0.28 Kg, final velocity is zero since it finally comes to rest, t is 0.00025 s and initial velocity is given as 7.2 s. Substituting these values we obtain
(b)
For the second ball, the mass is also 0.28 Kg but its initial velocity is taken as zero, the final velocity of the second ball will be equal to the initial velocity of the second ball, that is 7.2 m/s and the time is also same, 0.00025 s. By substitution
Here, we prove that action and reaction are equal and opposite