We could use the change of pressure to calculate for the height climbed by the mountain hiker. The change of pressure is given by
p = rho * g * h, where p is the change of pressure, rho is the air density, g is the acceleration due to gravity, and h is the height.
Using the conversion 1 mbar = 100 Pa,
(930 - 780)(100) = (1.20)(9.80)h
15000 = 1.20*9.80*h
h = 1.28 km
Answer:
5501 kg/m^3
Explanation:
The value of g at the Earth's surface is

where G is the gravitational constant
M is the Earth's mass
is the Earth's radius
Solving the formula for M, we find the value of the Earth's mass:

The Earth's volume is (approximating the Earth to a perfect sphere)

So, the average density of the Earth is

Answer:
It is best to hold the umbrella at an angle which is parallel to the direction of rain drops.
Explanation:
Velocity of vector of rain drops plays crucial role here. Direction of the wind causes the rain drop directions. Hence handle of the umbrella should be parallel to the direction of rain drops. there will be more umbrella area if we keep umbrella in the direction.
We have a wave function: D(y,t) and we want to know some things about it. 1. The direction the wave is travelling is negative y direction or -y. 2. Since sound waves are longitudinal waves, this sound wave is oscillating along the y axis. 3. The wavelength we can get from k=2π/λ, k is the wave number, λ is the wavelength. So λ=2π/k=6.28/8.96=0.7 m. 4. Before i get the wave speed i will calculate the period of oscillation. It can be calculated from: ω=2πf where ω is angular frequency and f is wave frequency. So f=ω/2π=3140/6.28=500 Hz and the period is T=1/f=1/500=0.002 s. 5. Wave speed is v=λ*f= 0.7*500=350 m/s.