The statement which best describes reversed polarity is
A magnetic field aligned in the opposite direction as the earth's present-day magnetic field.
What is magnetic field?A magnetic field is described as a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials.
On the other hand, reversed polarity is described as to a period in the Earth's history when the orientation of the Earth's magnetic field was the opposite of its present-day orientation.
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In an experiment two identical rocks are simultaneously thrown from the edge of a cliff a distance h0 above the ground. Rock A is thrown vertically upward with speed v0
and rock B is thrown vertically downward with speed v0. Rock A and rock B strike the ground at times tA and tB, respectively. Consider the positive vertical direction to be upward.
Question: Rock B hits the ground at time tB. Derive an equation for the time tA it takes rock A to hit the ground in terms of v0,tB, and physical constants, as appropriate.
Answer:
We can use the kinematic equations of motion to derive an equation for the time tA it takes rock A to hit the ground in terms of v0, tB, and physical constants. Since rock A is thrown vertically upward, we can use the equation:h = v0t - (1/2)gt^2where h is the initial height of the rock, v0 is the initial velocity, g is the acceleration due to gravity (9.8 m/s^2), and t is the time. When rock A hits the ground, its final height is zero. So we can set h = 0 and solve for t:0 = v0tA - (1/2)gtA^2tA = (2v0)/gThis is the equation for the time it takes rock A to hit the ground. It is in terms of v0 and g, which are physical constants, and does not explicitly involve tB. However, we can use the fact that rock B hits the ground at time tB to relate tB to tA. Since rock B is thrown vertically downward, we can use the same kinematic equation with a negative value for g:h = -v0t + (1/2)gt^2When rock B hits the ground, its final height is also zero, so we can set h = 0 and solve for tB:0 = -v0tB + (1/2)gtB^2tB = (2v0)/gThis equation is identical to the equation we derived for tA. Therefore, we can conclude that both rocks hit the ground at the same time, regardless of the direction in which they were thrown.Therefore, the equation for the time tA it takes rock A to hit the ground in terms of v0, tB, and physical constants is:tA = (2v0)/gwhere v0 is the initial velocity and g is the acceleration due to gravity.
Explanation:
The time it takes for rock A to hit the ground after being thrown upwards can be calculated using the equation tA = (v0 / g) + sqrt((v0 / g)^2 + 2h0 / g). By substituting the time it takes for rock B to hit the ground (tB), we receive tA = tB + sqrt((tB^2) + 2h0 / g) with g as the acceleration due to gravity.
Explanation:In Physics, the time it takes for an object to hit the ground after being thrown upwards may be calculated with the equation tA = (v0 / g) + sqrt((v0 / g)^2 + 2h0 / g), where 'g' is the acceleration due to gravity. This equation emerges from the relationship of time and displacement in free fall motion. 'v0' was the initial upwards velocity, 'h0' is the height of the cliff, and 'g' stands for gravitational acceleration which is a constant 9.8m/s².
The time that it takes rock B (which was thrown downwards) to hit the ground may be calculated from the equation, tB = sqrt((2h0) / g). Knowing that tA equals tB, we can substitute tB into the equation for tA, which results in tA = tB + sqrt((tB^2) + 2h0 / g).
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Find the vector whose magnitude is 36 and inclination is 60°.
The vector whose magnitude is 36 and inclination is 60° is v = <18, 18√(3)>.
The inclination of a vector is the angle between the vector and a reference line. In this case, the reference line is the horizontal axis. Let the components be x and y. We know that the magnitude of the vector is 36, so,
magnitude = √(x² + y²) = 36
Squaring both sides of this equation, we get,
x² + y² = 1296
We also know that the inclination is 60°. The tangent of 60° is √(3), which is equal to the ratio of the vertical component to the horizontal component of the vector,
tan(60°) = y/x
y/x= √(3)
Multiplying both sides by x, we get,
y = √(3)x
Now we can substitute y in terms of x in the equation x² + y² = 1296,
x² + (√(3)x)² = 1296
Simplifying this equation, we get,
4x² = 1296
x² = 324
Taking the square root of both sides, we get,
x = +/- 18
Since the vector is making an angle of 60° with the horizontal, it must be in the first or fourth quadrant, where x is positive. Therefore, we take x = 18. Using y = √(3)x, we get,
y = sqrt(3)18
y = 18√(3)
So the vector is,
v = <18, 18√(3)>
Therefore, the vector whose magnitude is 36 and inclination is 60° is v = <18, 18√(3)>.
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