Answer:
1.8 m/s
Explanation:
Draw a free body diagram of the block. There are four forces:
Normal force Fn up.
Weight force mg down.
Applied force F to the east.
Friction force Fn μ to the west.
Sum the forces in the y direction:
∑F = ma
Fn − mg = 0
Fn = mg
Sum the forces in the x direction:
F − Fn μ = ma
F − mg μ = ma
a = (F − mg μ) / m
a = (12 N − 6 kg × 9.8 m/s² × 0.15) / 6 kg
a = 0.53 m/s²
Given:
Δx = 3 m
v₀ = 0 m/s
a = 0.53 m/s²
Find: v
v² = v₀² + 2aΔx
v² = (0 m/s)² + 2 (0.53 m/s²) (3 m)
v = 1.8 m/s
Given that,
Distance, d = 10700 km
Time taken by the airplane to complete the destination, t = 12 hours
We need to find the speed of the airplane. It is equal to the total distance covered divided by total time taken. So,

We know that,
1 km = 1000 m
1 h = 3600 s
So,

So, the speed of the airplane is 891.66 km/h or 247.68 m/s.
270/70^2 = x/80^2
Cross multiply
270 (6400) = 4900x
x = 270(6400)/4900
352 and 32/49 feet
Hope this helps
Answer:
1. In general, the best shields will be able to block a spectrum of radiation. Aboard the space station, the use of hydrogen-rich shielding such as polyethylene in the most frequently occupied locations, such as the sleeping quarters and the galley, has reduced the crew's exposure to space radiation.
2. It absorbs harmful ultraviolet radiation from the sun, helps keep Earth's surface warm via the greenhouse effect, and reduces temperature extremes between day and night. ... So, thanks to gravity, although some of Earth's atmosphere is escaping to space, most is staying here.
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