We use the formula,
.
Here, v is velocity and its value given 26 mi/h ( in m/s, 
) and d is distance and its value is given 80 m.
Substituting these values in above formula we get,
Thus, the time delay between green lights on successive blocks to keep the traffic moving continuously is 6.88 s
Low coefficient of friction
1. flying a plane (friction between air and plane)
2. ice skating (friction between ice and skate blade)
3. swimming (water & skin)
4. rowing a boat (water and boat)
Answer:
20 degrees.
Explanation:
From Snell’s law of refraction:
sinθ1•n1 = sinθ2•n2
where θ1 is the incidence angle, θ2 is the refraction angle, n1 is the refraction index of light in medium1, and n2 is the refraction index for virgin olive oil. The incidence angle of the red light is θ1 = 30 degrees.
The red light is in air as medium1, so n1 (air) = 1.00029
So, to find θ2, the refracted angle:
sinθ1•1.00029 = sinθ2•1.464
sin(30)•1.00029 / 1.464 = sinθ2
0.5•1.00029 / 1.464 = sinθ2
sinθ2 = 0.3416291
θ2 = arcsin(0.3416291)
θ2 = 19.976 degrees
To the nearest degree,
θ2 = 20 degrees.
