Asuspension bridge is 60.0 m above the level base of a gorge. a stone is thrown or dropped from the bridge. ignore air resistance. at the location of the bridge g has been measured to be 9.83 m/s2. (a) if you drop the stone, how long does it take for it to fall to the base of the gorge? (b) if you throw the stone straight down with a speed of 20.0 m/s, how long before it hits the ground? (c) if you throw the stone with a velocity of 20.0 m/s at 30.0° above the horizontal, how far from the point directly below the bridge will it hit the level ground?

a)

b)

c)Xmax=80.71m

Explanation:

a)Kinematics equation for the Stone, dropped:

      initial position is bridge height

      the stone is dropped

The ball reaches the ground, y=0, at t=t1:

b)Kinematics equation for the Stone, with a initial speed of 20m/s:

      initial position is bridge height

      the stone is thrown straight down

The ball reaches the ground, y=0, at t=t1:

t2=-6.01       this solution does not have physical sense

t2=2.00

c)Kinematics equation for the Stone, with a initial speed of 20m/s with an angle of 30° above the horizontal:

      initial position is bridge height

      the stone is thrown with an angle of 30° above the horizontal

The ball reaches the ground, y=0, at t=t3:

t3=-2.62       this solution does not have physical sense

t3=4.66

the movement in x:

v=constant=20cos(30)m/s

x(t)=v*t

Xmax=v*t3=20cos(30)*4.66=80.71m

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.