Tim and Rick both can run at speed vr and walk at speed vw, with vr>vw. They set off together on a journey of distance D. Rick walks half of the distance and runs the other half. Tim walks half of the time and runs the other half. 1. How long does it take Rick to cover the distance D?
2. Find Rick's average speed for covering the distance D.
3. How long does it take Tim to cover the distance?
4. Who covers the distance D more quickly?
5. In terms of given quantities, by what amount of time, Delta t, does Tim beat Rick?

Explanation:

1

t = D/2(vw) + D/2(vr)

2

V(ave) = 2.v(r).v(w) / [v(r) + v(w)]

3

t(T) = 2D / [v(w) + v(r)]

4

Tim does

5

in simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g. this is also known as upthrust.

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.