Answer:
The speed of the plank is 81.68 m/s
Explanation:
Given that,
Speed of bullet = 152 m/s
Speed of wood = 128 m/s
Speed of another bullet = 97 m/s
We need to calculate the speed of plank
Using conservation of momentum
Where,
u = initial velocity
v = final velocity
....(I)
....(II)
From equation(I) and equation(II)
Hence, The speed of the plank is 81.68 m/s
Answer:
a) 1 m tall, 3 m wide
b) 1 m tall, 1.31 m wide
Explanation:
According to the captain of the spaceship, the dimensions of the picture is the same i.e 1.0 m tall along the y' axis and 3.0 m wide along the x' axis.
b) The dimensions of the picture as seen by an observer on the Earth along the y axis will remain the same, 1.0 m tall, for the direction of the y axis is perpendicular to the spaceship movement.
The dimensions of the picture as seen by an observer on the Earth along the x axis will reduce if we are to go by the Lorentz contraction:
L(x) = L(x)' * √[1 - (v²/c²)]
where
L(x)' = the dimensions of the picture along the x axis on the spaceship,
v² = the speed of the spaceship and c² = the speed of light in the vacuum.
On substituting, we have
L(x) = 3 * √[1 - (0.81c²/c²)]
L(x) = 1.31 m
Given:
The length of the string is l = 6 m
The speed of the wave is
Required: Lowest possible frequency for the standing wave.
Explanation:
The lowest possible frequency is the fundamental frequency.
The fundamental frequency can be calculated by the formula
On substituting the values, the fundamental frequency will be
Final Answer: The lowest possible frequency for standing waves on this string is 16.67 Hz
Answer:
d
Explanation:
uv is safe for humans but bad for bacteria etc... at least I think. I'm sorry if I'm wrong
Answer:
2513.6 W
Explanation:
Acoustic power = sound intensity × area of hemisphere
Sound intensity = 1 W/m^2
Area of hemisphere = 2πr^2 = 2×3.142×20^2 = 2513.6 m^2
Acoustic power = 1 W/m^2 × 2513.6 m^2 = 2513.6 W
