Answer:
4.47 m/s.
Explanation:
distance traveled, d = 10 miles
time, t = 1 hour
Speed of the runner, v = d / t
Speed of the runner = 10 miles / 1
Speed of the runner = 10 mph
1 mph ----------------------- 0.44704 m/s
10 mph -----------------------?
= 4.47 m/s
Thus, in 2 hours the distance traveled will change but the speed it still 10 mph or 4.47 m/s.
-- Multiply each side of the formula by 2
-- Then divide each side by t
-- Then subtract V(i) from each side.
A) 4.7 cm
The formula for the angular spread of the nth-maximum from the central bright fringe for a diffraction from two slits is

where
n is the order of the maximum
is the wavelength
is the distance between the slits
In this problem,
n = 5


So we find

And given the distance of the screen from the slits,

The distance of the 5th bright fringe from the central bright fringe will be given by

B) 8.1 cm
The formula to find the nth-minimum (dark fringe) in a diffraction pattern from double slit is a bit differente from the previous one:

To find the angle corresponding to the 8th dark fringe, we substitute n=8:

And the distance of the 8th dark fringe from the central bright fringe will be given by

V = 1/3 Bh v = 1/3 (13 ac)(43560ft^2/ac)(481ft) v = 90793560 ft^3 * 0.3048m/ft * 0.3048m/ft * 0.3048m/ft = 2570987m^3