I know that the relationship between altitude and atmospheric density is that the higher the altitude, the lesser the density, and the lower the altitude the higher the density. Lower density float to the top, and higher density is 'heavy' so it comes down

6 0

3 years ago

A box of mass 50 kg is pushed hard enough to set it in motion across a flat surface. Then a 99-N pushing force is needed to keep

salantis [7]

The box is kept in motion at constant velocity by a force of F=99 N. Constant velocity means there is no acceleration, so the resultant of the forces acting on the box is zero. Apart from the force F pushing the box, there is only another force acting on it in the horizontal direction: the frictional force $F_f$ which acts in the opposite direction of the motion, so in the opposite direction of F.
Therefore, since the resultant of the two forces must be zero,
$F-F_f=0$
so
$F=F_f$

The frictional force can be rewritten as
$F_f = \mu m g$
where $m=50 kg$ , $g=9.81 m/s^2$ . Re-arranging, we can solve this equation to find $\mu$ , the coefficient of dynamic friction:
$\mu = \frac{F}{mg}= \frac{99 N}{(50 kg)(9.81 m/s^2)} =0.20$

4 0

3 years ago

Why are objects that fall near Earth’s surface rarely in free fall?

bulgar [2K]

<span>Objects that fall near Earth’s surface are rarely in free fall.

"Free fall" is the situation where the ONLY force on an object is
the force of gravity, and nothing else.

Objects near Earth's surface are almost always surrounded by air.
If they are falling, then the air is exerting forces on them, and they
are not in "free fall".</span>

4 0

3 years ago

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