Why are objects that fall near Earth's surface rarely in free fall?
1 answer:
Answer: Air exerts forces on falling objects near Earth's surface.
Explanation: Objects falling near the earth surface are rarely in free fall due to the force exerted by air on falling object near the earth( air resistance).
The acceleration of free fall tend to pull the body towards the earth surface while air resistance (drag) tends to act in the opposite direction.
Given that the weight of the body is always constant.
The drag acts in the upward direction, thereby negating the downward weight of the object.
From Newton's Second law:
Force = mass × acceleration due to gravity
Acceleration = force / mass
The net force acting on the object becomes :
(Downward weight - upward drag)
This hampers the free fall of the object due to gravity.
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Answer:
✓ A cyclone device accumulates fine particulates from the air by making a dirty air stream flow in a spiral path inside a cylindrical chamber.
✘ It consists of several long and narrow fabric filter bags suspended upside-down in a large enclosure.
✓ When dirty air enters the chamber, the larger particulates strike the chamber wall and fall into a conical dust hopper at the bottom.
✘ Fans blow dirt-filled air upward from the bottom of the enclosure, trapping dirt particles inside the filter bags and releasing clean air from the top.
✓ The top of the chamber has an outlet that lets out cleaned air.
Basically, any of these choices that have the word "filter" are wrong. The point of the cyclone device is to separate the particles without the use of filters. You can tell the right answers based on the picture attached below.
Answer:
The frequency of infrared wave is 35.385 GHz
Explanation:
Given data:
Wavelength of infrared light = 8.45 mm = 8.45 x m
Velocity of infrared light = 2.99 x m/s
To find: frequency of the infrared wave = ?
We know that the wavelength and frequency are inversely proportional and the formula to derive frequency with velocity and wavelength is:
c = μλ, where
c is velocity of light
μ is frequency of light
λ is wavelength of light
Hence the frequency of light μ = c/λ
=
= x
= 35.385 x Hz (since 1
= 1 Hz)
= 35.385 GHz
Answer: Minimum speed needed by the Olympic champion at launch if he was traveling at 6.8 m/s at the top of the arc is 11.65 m/s.
Explanation:
Velocity is only in horizontal direction at the top most point which is similar to the velocity in the horizontal direction at the time of launch.
Now, according to the law of conservation of energy the formula used is as follows.
As speed at which the person is travelling was 6.8 m/s. Hence, the initial velocity will be calculated as follows.
Thus, we can conclude that minimum speed needed by the Olympic champion at launch if he was traveling at 6.8 m/s at the top of the arc is 11.65 m/s.