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
The middle or centre of the Earth is the core. However the middle of the layers from the surface to the centre of the Earth is known as mantle.
Answer: D. 0.5
Explanation:
The slope formula is y2-y1/x2-x1.
2-(-1)/4-(-2) = 2+1/4+2
2+1/4+2 = 3/6 = 1/2
1/2 = 0.5
The slope is 1/2, or 0.5.