Sound waves in air (and any fluid medium) are longitudinal waves because particles of the medium through which the sound is transported vibrate parallel to the direction that the sound wave moves.
The correct matching are the following:
- A. magnetic field: prevents charged particles from the sun from reaching the surface
- B. ozone: filters cancer-causing rays from the sun
- C. carbon dioxide: retains heat energy from the sun in the atmosphere
- D. water in oceans, lakes, rivers and streams: moderates changes in temperature on the surface
The electromagnetic field of the Earth protects us from solar wind by deflecting it. Without it, the charged particles would strip away our ozone, which will lead to the end of life on Earth.
The ozone is a layer in the stratosphere that filters the suns rays. It filters the UV rays by absorbing it. This prevents the UV rays from damaging the surface of the Earth.
Carbon dioxide retains heat in the atmosphere, which creates a greenhouse effect. It is beneficial for us, but because human activity like industrial activities emit so much carbon in the atmosphere that it ends up being harmful.
Bodies of water found on Earth regulate the temperature of the Earth through ocean currents. It brings in both cold and warm air to land which also affect precipitation.
Long explanation, I know, but maybe this will help you out in the long run. Good Luck!
Let's break the question into two parts:
1) The force needed in Ramp scenario.
2) The effort force needed in the lever scenario.
1. Ramp Scenario: In an incline, the only component of cart's weight(
mg) that is in the direction of motion is
. Therefore the effort force in this case must be equal or greater than
.
Now we need to find

.

is the angle between the incline of the ramp and the ground.
Since the height is
5m and the length of the ramp is
8m, 
would be
5/8 or 0.625. Now that you have

, mutiple it with
mg.
=> m*g*

= 20 * 10 * 5 / 8. (Taking g = 10 m/s² for simplicity) = 125N
Therefore, the minimum Effort force you would require in this case is
125N.
2. Lever Scenario:
Just apply "moment action" in this case, which is:


= ?

= mg = 20 * 10 = 200N

= 10m

= 1m
Plug-in the values in the above equation:

= 200/10=
20NAs 20N << 125N, the best choice is to use lever.
The driver is tooling along in his snowmobile, pointed north,
at 8.5 m/s.
He's carrying the flares with him, so the flares are also moving north
at 8.5 m/s.
When he fires the flare straight up, it has a vertical velocity of 4.3 m/s
straight up, and a horizontal velocity of 8.5 m/s towards the north.
The magnitude of the net velocity is √(4.3² + 8.5²) .
That's about 9.53 m/s, at some angle between straight up
and straight north.
The angle above horizontal is the angle that has a tangent of 4.3/8.5 .
I'll let you work out the angle.
Answer:
F= 134.92 N
Explanation:
Given that
The mass of the moon ,M = 7.4 x 10²² kg
The mass of the man ,m = 79 kg
The radius ,R= 1.7 x 10⁶ m
The force exerted by moon is given as

Now by putting the values in the above equation we get

Therefore the force will be 134.92 N.
F= 134.92 N