Answer:
Kepler's first law suggests that the orbit of planets is not circular but elliptical
Explanation:
The three Kepler's laws explain the motion of the planets orbiting the Sun:
- The first law tells that the orbits of the planets around the Sun are ellipses, with the Sun located at one of the two focii
- The second law tells that a line connecting the Sun with the planet sweeps out equal areas in equal amounts of time
- The third law tells that the square of the orbital periods of the planets is proportional to the cube of their average distance from the Sun
As we can read, the first law tells us that the orbit of the planets is not circular, but elliptical.
Answer:
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Explanation:
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Answer: The correct answer is longitudinal wave.
Explanation:
Longitudinal wave: The vibration of the particle is parallel to the direction of the propagation of the wave.
Longitudinal wave consists of the compression and the rarefaction.
Compression is the region where the density of the particles are more. Rarefaction is the region where the density of the particles are less.
The example of the longitudinal wave is Sound wave.
pushed with a force of 378 N exerted downward at an angle of 25.6◦ below the horizontal.
Find µk between the box and the floor.
Answer:
Approximately , assuming that the floor is level.
Explanation:
Between two surfaces that are moving relative to one another, the coefficient of kinetic friction is equal to the ratio between friction and normal force.
Since the box in this question is moving at a constant speed, the box would be in a translational equilibrium. Forces on this box should be balanced in both the horizontal component and the vertical component.
The value of in this question can be found in the following steps:
At an angle of from the horizontal, magnitude of the vertical and horizontal components of the external force would be:
Assume that the floor is level. Forces on this object in the horizontal direction would include:
Forces on this object are balanced in the horizontal direction. Hence, the magnitude of friction would be equal to that of the horizontal component of the external force:
.
Forces on this object in the vertical direction would include:
Forces on this object in the vertical direction are also balanced. The magnitude of the normal force (pointing upward) should be equal to the sum of the magnitude of the two forces pointing downward:
.
It is given that the magnitude of the weight of this object is . To find the coefficient of kinetic friction, divide the magnitude of friction by the magnitude of the normal force:
.