The two types of mechanical waves are longitudinal waves, and transversal waves.
Answer:
Time, t = 8 seconds
Explanation:
An object is thrown upward from the top of a 128-foot building with an initial velocity of 112 feet per second. The height h as a function of time t is given by :

We need to find the time when the object will hit the ground. When it will hit the ground, h = 0
So,

On solving the above quadratic equation, we get the value of t = 8 seconds. So, after 8 seconds the object will hit the ground. Hence, this is the required solution.
Person standing on A will hear the loudest sound
Explanation:
The intensity of a sound wave (which is proportional to the loudness of the sound) follows an inverse square law, which is:

where
I is the intensity of the wave
r is the distance from the source of the sound
This equation means that the intensity of the sound wave (and therefore, its loudness) is inversely proportional to the square of the distance from the source: therefore,
- As we get closer to the source of sound, the loudness increases
- As we move away from the source of sound, the loudness decreases
Therefore, the person that will hear the loudest sound is the one standing closer to the source, and therefore person A.
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Answer:
y = 0.99 m
Explanation:
This is a projectile launching exercise, let's start by finding the components of the initial velocity, using trigonometry
cos θ = v₀ₓ / v₀
sin θ = v_{oy} / v₀
v₀ₓ = vo cos θ
v_{oy} = I go sin θ
v₀ₓ = 15 cos 30 = 12.99 m / s
v_{oy} = 15 sin 30 = 7.5 m / s
Let's find the time it takes to travel x = 18 m
x = v₀ₓ t
t = x / v₀ₓ
t = 18 / 12.99
t = 1,385 s
at this point it is at a height of
y = v_{oy} - ½ g t²
y = 7.5 1.385 - ½ 9.8 1.385²
y = 0.99 m
therefore the camera must place the foot 99 cm from the ground
Explanation:
Given
Ball is projected horizontally from a building of height 
time taken to reach ground is given by

(b) Line joining the point of projection and the point where it hits the ground makes an angle of 
From the figure, it can be written

Considering horizontal motion

(c) The vertical velocity with which it strikes the ground is given by

Thus, the ball strikes with a vertical velocity of 