Given:
u = 7.00m/s, the initial vertical velocity of the package.
Assume that g = 9.8 m/s².
Neglect air resistance.
All quantities are measured as positive upwards.
The height from which the package is dropped is 155 m above ground.
Let t = the time for the package to hit the ground.
Therefore
(7.00 m/s)*(t s) - (1/2)*(9.8 m/s²)*(t s)² = (- 155 m)
4.9t² - 7t - 155 = 0
or
t² - 1.4286t - 31.6327 0
Solve with the quadratic formula.
t = (1/2)*[1.4286 +/- √(2.0409 + 126.5308)]
= 6.384 s or - 4.955 s
Reject negative time.
Answer: 6.384 s
U=mgh
U=10*9.8*20
U=1960
Answer is D
Solution :
Philosophy is idealism
The idealism is considered as a philosophical approach where the main belief is that 'ideas' are the only true realities and it is the only thing that is worth knowing.
Philosophy in cynicism
In cynicism philosophy, it is belief that the purpose of the life is to live in the virtue and in agreement with the nature. They are practiced by the cynics.
Philosophy in stoicism
Stoicism is a philosophy that hails from Rome and Greece. It beliefs in life that provides maximum positive emotions of the people, and it reduces negative emotions. they also believes that it helps people to hone their virtues of the characters.
Answer:
There are many kinds of waves all around us. There are waves in the ocean and in lakes. Did you also know that there are also waves in the air? Sound travels through the air in waves and light is made up of waves of electromagnetic energy.
The wavelength of a wave describes how long the wave is. The distance from the "crest" (top) of one wave to the crest of the next wave is the wavelength. Alternately, we can measure from the "trough" (bottom) of one wave to the trough of the next wave and get the same value for the wavelength.
The frequency of a wave is inversely proportional to its wavelength. That means that waves with a high frequency have a short wavelength, while waves with a low frequency have a longer wavelength.
Light waves have very, very short wavelengths. Red light waves have wavelengths around 700 nanometers (nm), while blue and purple light have even shorter waves with wavelengths around 400 or 500 nm. Some radio waves, another type of electromagnetic radiation, have much longer waves than light, with wavelengths ranging from millimeters to kilometers.
Sound waves traveling through air have wavelengths from millimeters to meters. Low-pitch bass notes that humans can barely hear have huge wavelengths around 17 meters and frequencies around 20 hertz (Hz). Extremely high-pitched sounds that are on the other edge of the range that humans can hear have smaller wavelengths around 17 mm and frequencies around 20 kHz (kilohertz, or thousands of Hertz).
Explanation: