Answer:
The sound intensity of train is 1000 times greater than that of the library.
Explanation:
We have expression for sound intensity level,
A train whistle has a sound intensity level of 70 dB
We have
A library has a sound intensity level of about 40 dB
We also have
Dividing both equations
The sound intensity of train is 1000 times greater than that of the library.
Answer:
9.39 m/s
Explanation:
Using the y-direction, we can solve for the time t it takes for the cart to reach the ground.
Assume the up direction is positive and the down direction is negative.
- v₀ = 0 m/s
- a = -9.8 m/s²
- Δy = -50 m
- t = ?
Find the constant acceleration equation that contains these four variables.
Substitute known values into this equation.
Multiply and simplify.
Divide both sides of the equation by -4.9.
Square root both sides of the equation.
Now we can use this time t and solve for v₀ in the x-direction. Time is most often our link between vertical and horizontal components of projectile motion.
List out known variables in the x-direction.
- v₀ = ?
- t = 3.194382825 s
- a = 0 m/s²
- Δx = 30 m
Find the constant acceleration equation that contains these four variables.
Substitute known values into the equation.
- 30 = (v₀ · 3.194382825) + 1/2(0)(3.194382825)²
Multiply and simplify.
Divide both sides of the equation by 3.194382825.
The cart was rolling at a velocity of 9.39 m/s (initial velocity) when it left the ledge.
Answer:
I guess the answer is
-The mass and volume of an object determine if it will sink or float
Explanation:
An object that has a higher density than the liquid it's in will sink. An object that has a lower density than the liquid it's in will float.
density=mass/volume
Answer:
y = 128.0 km
Explanation:
The minimum separation of two objects is determined by Rayleygh's diffraction criterion, which establishes that two bodies are solved if the first minino of diffraction of one coincides with the central maximum of the second, with this criterion the diffraction equation remains
the diffraction equation for the first minimum is
a sin θ = λ
In the case of circular openings, the equation must be solved in polar coordinates, leaving the expression, we use the approximation that the sine of tea is very small.
θ = 1.22 λ / d
d = 15 cm
to find the distance we can use trigonometry
tan θ = y / L
tan θ = sin θ / cos θ = θ
substituting
y / L = λ / d
y = L λ /d
let's calculate
y = 384 10⁸ 500 10⁻⁹ / 0.15
y = 1.28 10⁵ m
Let's reduce to km
y = 1.28 10⁵ m (1km / 10³ m)
y = 128.0 km
the correct answer is 120 km away