Answer: Scientists found evidence of Earths magnetic field reversal in rocks on the ocean floor at plate boundaries. These rocks have alternating polarity due to magnetization that occurred during their cooling period. Using radio metric dating, scientist estimate that reversals occur approximately every several hundred thousand years.
Explanation:
Answer: a.) Roughness of the surfaces in contact with each other .
Higher the roughness of surfaces in contact with each other, greater is the friction between bodies. Force of friction will be less between smooth surfaces.
b.) Weight of the sliding/rolling body: greater the weight of the moving body on the surface, more is the force of friction on the body by the surface.
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Answer:
Explanation:
The tip of the second hand moves on a circular path having radius equal to .22 m . Redial acceleration is given by the expression
ω²R where ω is angular velocity and R is radius of the circular path .
angular velocity of second hand = 2π / T where T is time period of circular motion . For second hand it is 60 s.
ω = 2π / T
= 2π / 60
= .1047
angular acceleration = .1047² x .22
= 2.41 x 10⁻³ rad / s² .
Answer:
Silicon tetrafluoride
Explanation:
The symbol Si represents the element silicon, as shown in the periodic table.
The are 4 fluorines, so the prefix for fluoride must have tetra-
The y-component of the initial velocity vector is zero only in scenarios A and C. The weight/package on either plane inherits a non-zero x-component that matches the plane's horizontal velocity, but with respect to the vertical direction the objects are at rest, and dropping them from a given height doesn't confer them an initial vertical velocity. On the other hand, if the object was thrown upward and allowed to fall, or shot downward by a cannon, then the initial vertical velocity would be non-zero.
In scenario B, the dolphin must have some non-zero y-component of velocity in order to launch itself out of the water, because otherwise it would stay at a fixed depth.
