Answer:
B. Two ends of a bulb are attached to the positive and negative poles of the battery
Explanation:
Answer:
m = 0.217 kg
Explanation:
We can solve this exercise using the conservation of angular momentum. For this the system is formed by the bar and the disk, so that the forces during the crash have been internal and the angular momentum is preserved
initial angular mount. Before impact
L₀ = L_bar + L_ disk
L₀ = I_bar w₀ + m r v₀
final angular momentum. Right after the crash
= I_bar wf = m r v_{f}
The moment of inertia of a bar that rotates at its ends is
I_bar = 1/12 M L
how the angular momentum is conserved
L₀ = L_{f}
I_barr w₀ + mr v₀ = I_barr w_{f} + m r v_{f}
I_bar (w₀- w_{f}) = m r (v₀- v_{f})) r
m = I_bar (w₀ - w_{f}) / r (v₀ -v_{f})
m = 1/12 M L (w₀ -w_{f} ) / r (v₀ -v_{f})
in the exercise it indicates that the initial speed of the disc is v₀ = 20 m / s and its final speed is v_{f} = -16 m / s, the negative sign is because the disc recoils
we calculate
m = 1/12 35 0.90 (0 + 1.14) / [0.30 (30- (-16))]
m = 0.217 kg
Answer:
Zero
Explanation:
It is given that,
A person swims to the other end of a 20m long pool and back.
We need to find his displacement.
Displacement = shortest path covered
He reaches at the same position as from where he has started. It means the shortest path covered is equal to 0 i.e. his displacement is zero.
Answer:
The intensity of a light from the source at a distance of 10 meters is 0.0026 foot-candle.
Explanation:
Given that,
Distance from the source = 2 meter
Intensity = 0.065 foot -candle
New distance = 10 m
We know that,
The intensity I of light varies inversely with the square of the distance from the source.
We need to calculate the value of constant
Using formula of intensity
![I=\dfrac{k}{x^2}](https://tex.z-dn.net/?f=I%3D%5Cdfrac%7Bk%7D%7Bx%5E2%7D)
Put the value into the formula
![0.065=\dfrac{k}{6.56168^2}](https://tex.z-dn.net/?f=0.065%3D%5Cdfrac%7Bk%7D%7B6.56168%5E2%7D)
![k=0.065\times(6.56168)^2](https://tex.z-dn.net/?f=k%3D0.065%5Ctimes%286.56168%29%5E2)
![k=2.798](https://tex.z-dn.net/?f=k%3D2.798)
We need to calculate the intensity
Using formula of intensity again
![I=\dfrac{k}{x^2}](https://tex.z-dn.net/?f=I%3D%5Cdfrac%7Bk%7D%7Bx%5E2%7D)
Put the value into the formula
![I=\dfrac{2.798}{32.8084^2}](https://tex.z-dn.net/?f=I%3D%5Cdfrac%7B2.798%7D%7B32.8084%5E2%7D)
![I=0.0026\ foot-candle](https://tex.z-dn.net/?f=I%3D0.0026%5C%20foot-candle)
Hence, The intensity of a light from the source at a distance of 10 meters is 0.0026 foot-candle.