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3 years ago

6

When an object moves away from Earth, its light waves are stretched to a lower frequency, or longer wavelength, and thus we say

the light is redshifted. True False

1 answer:

Gelneren [198K]3 years ago

3 0

Your answer will be False because wavelengths are usually are use as sound waves.

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Plsssss asappppppppp

KengaRu [80]

Answer:

20 meters.

Explanation:

In the graph, the x-axis (the horizontal axis) represents the time, while the y-axis (the vertical axis) represents the distance.

If we want to find the distance covered in the first T seconds, you need to find the value T in the horizontal axis.

Once you find it, we draw a vertical line, in the point where this vertical line touches the graph, we now draw a horizontal line. This horizontal line will intersect the y-axis in a given value. That value is the total distance travelled by the time T.

In this case, we want to find the total distance that David ran in the first 4 seconds.

Then we need to find the value 4 seconds in the horizontal axis. Now we perform the above steps, and we will find that the correspondent y-value is 20.

This means that in the first 4 seconds, David ran a distance of 20 meters.

6 0

3 years ago

A car starts from rest and undergoes an acceleration of 4.0 m/s/s for a time of 5.0 s. What is the final velocity of the car?

Kruka [31]

Answer:

20m/s

Explanation:

acceleration=final velocity-initial velocity/time

4.0m/s²=v m/s-0m/s/5.0sec

5.0sec×4.0m/s²=v m/s-0m/s×5.0m/s/5.0m/s

20m/s=v

7 0

3 years ago

How do you find the direction of displacement?

andreyandreev [35.5K]

You draw a straight line from the start point to the end point. It doesn't matter what route was actually followed for the trip.

3 0

3 years ago

NASA is designing a Mars-lander that will enter the Martian atmosphere at high speed. To land safely it must slow to a constant

Viktor [21]

Answer:

a) maximum mass of the Mars lander to ensure it can land safely is 200 kg

b) area of the parachute required is 480 m² which is larger than 400 m²

c) area of the parachute should be 12.68 m²

Explanation:

Given the data in the question;

V = 20 m/s

A = 200 m²

drag co-efficient CD = 1.855

g = 3.71 m/s²

density of the atmospheric pressure β = 0.01 kg/m³

a. Calculate the maximum mass of the Mars lander to ensure it can land safely?

Drag force FD = 1/2 × CD × β × A × V²

we substitute

FD = 1/2 × 1.855 × 0.01 kg/m × 200 m² × ( 20 m/s )²

FD = 742 N

we know that;

FD = Fg

Fg = gravity force

Fg = mg

so

FD = mg

m = FD/g

we substitute

m = 742 N / 3.71 m/s²

m = 200 kg

Therefore, the maximum mass of the Mars lander to ensure it can land safely is 200 kg

b. The mission designers consider a larger lander with a mass of 480 kg. Show that the parachute required would be larger than 400 m²;

Given that;

M = 480 kg

Show that the parachute required would be larger than 400 m²

we know that;

FD = Fg = Mg = 480 kg × 3.71 m/s²

FD = 1780.8 N

Now, FD = 1/2 × CD × β × A × V², we solve for A

A = FD / 0.5 × CD × β × V²

we substitute

A = 1780.8 / 0.5 × 1.855 × 0.1 × (20)²

A = 1780.8 / 3.71

A = 480 m²

Therefore, area of the parachute required 480 m² which is larger than 400 m²

c. To test the lander before launching it to Mars, it is tested on Earth where g = 9.8 m/s^2 and the atmospheric density is 1.0 kg m-3. How big should the parachute be for the terminal speed to be 20 m/s, if the mass of the lander is 480 kg?

Given that;

g = 9.8 m/s²,

β" = 1 kg/m³

v" = 20 m/s

M" = 480 kg

we know that;

FD = Fg = M"g

FD = 480 kg × 9.8 m/s² = 4704 N

from the expression; FD = 1/2 × CD × β × A × V²

A = FD / 0.5 × CD × β" × V"²

we substitute

A = 4704 / 0.5 × 1.855 × 1 × (20)²

A = 4704 / 371

A = 12.68 m²

Therefore area of the parachute should be 12.68 m²

3 0

3 years ago

An igneous rocks color is mainly determined by its

melomori [17]

An ignious rock's color is mainly determined by its silica content

4 0

3 years ago