Use this formula for an object starting from rest and accelerating:
Distance = (1/2) (acceleration) (time)²
In this problem, the distance is 40 meters, and acceleration is gravity.
So . . .
40 m = (1/2) (9.8 m/s²) (time)²
Divide each side by (4.9 m/s²) :
time² = (40 m) / (4.9 m/s²)
time² = 8.16 sec²
Take the square root of each side :
√(time²) = √(8.16 sec²)
time = 2.86 seconds
Round it to 2.9 sec <em>(choice B)</em>
Answer:
The answer is letter B, absorb.
Explanation:
Heat travels through three different ways: radiation,conduction and convection.
Radiation- this happens when heat moves as energy waves (infrared waves) directly from its source to something.
Conduction- heat passes directly from one object to another through the touching of surfaces.
Convection- this occurs when warmer areas of a liquid or gas rise to cooler areas in the liquid or gas.
The transfer of heat in the situation above is an example of "thermal radiation." The campfire carries light energy through the fire. These consists of electromagnetic waves (most of these are infrared light). These waves (radiation) carry energy, which is then converted to heat once it hits another object that absorbs it. In the case above, once the hands absorbs the energy, it then warms up. This happened because the hands are placed <u><em>near the campfire.</em></u> Placing the hands near the campfire is important because air is a poor thermal conductor.
Thus, the answer above is letter B, absorb.
The visible radiation produced by new stars within a molecular cloud get absorbed by dust grains and heats up the cloud
A molecular cloud is an interstellar cloud of gas and dust in which molecules can form, the most common of which is hydrogen .
The formation of stars occurs exclusively within molecular clouds because of their low temperatures and high densities, because the gravitational force acting to collapse the cloud must exceed the internal pressures that are acting "outward" to prevent a collapse.
Visible radiation are absorbed by dust grains and heats up the cloud as it cannot penetrate through the cloud instead get absorbed by the cloud . Newly formed stars are visible nearby, their images reddened by blue light which got scattered by the pervasive dust.
To learn more about molecular clouds here
brainly.com/question/3459894
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Explanation:
In uniform gravity it is the same as the centre of mass. For regular shaped bodies it lies at the centre of the that particular body. Hence for a cylinder centre of gravity lies at the midpoint of the axis of the cylinder.
