Answer:
a) about 20.4 meters high
b) about 4.08 seconds
Explanation:
Part a)
To find the maximum height the ball reaches under the action of gravity (g = 9.8 m/s^2) use the equation that connects change in velocity over time with acceleration.
In our case, the initial velocity of the ball as it leaves the hands of the person is Vi = 20 m/s, while thw final velocity of the ball as it reaches its maximum height is zero (0) m/s. Therefore we can solve for the time it takes the ball to reach the top:
Now we use this time in the expression for the distance covered (final position Xf minus initial position Xi) under acceleration:
Part b) Now we use the expression for distance covered under acceleration to find the time it takes for the ball to leave the person's hand and come back to it (notice that Xf-Xi in this case will be zero - same final and initial position)
To solve for "t" in this quadratic equation, we can factor it out as shown:
Therefore there are two possible solutions when each of the two factors equals zero:
1) t= 0 (which is not representative of our case) , and
2) the expression in parenthesis is zero:
Answer:
1) Because of the size and time the sound wave moves, an echo is typically transparent and easy to discern. Since reverberations typically don't have enough distance or time to fly, they will pile up on top of each other, making it impossible to understand.
People will detect an echo if the distance between the source of the sound and the reflected body is greater than 50 feet. When a sound wave is bounced off a nearby surface, it may create a reverberation.
2) The speed of sound in hot air is more than that in cold air because air molecules are traveling faster in hot air.
Explanation:
Answer:
frequency = 5.52 * 10² Hz
Explanation:
the equation that relates velocity, frequency and wavelength is:
velocity = frequency * wavelength
We are given that:
velocity = 331 m/sec
wavelength = 0.6 m
Substitute with the givens in the equation to get the frequency as follows:
velocity = frequency * wavelength
331 = frequency * 0.6
frequency = 331 / 0.6
frequency = 5.52 * 10² Hz
Hope this helps :)
Answer:
Explanation:
velocity of ship with respect to water = 6.5 m/s due north
velocity of water with respect to earth = 1.5 m/s at 40° north of east
velocity of ship with respect to water = velocity of ship with respect to earth - velocity of water with respect to earth
The magnitude of the velocity of ship relative to earth is = 5.66 m/s
Answer:
3,3*10^-11 J
Explanation:
A=Uq=2,08*10^8 V * 1,6*10^-19 C=3,3*10^-11J