Blood is accelerated from rest to 25.00 cm/s in a distance of 2.10 cm by the left ventricle of the heart. how long does the acceleration take? (to solve this problem, first identify the unknown, and then discuss how you chose the appropriate equation to solve for it. after choosing the equation, show your steps in solving for the unknown, checking your units.)

Time taken, t = 0.16 seconds

Explanation:

Given that,

Initial speed of blood, u = 0

Final speed of blood, v = 25 cm/s = 0.25 m/s

Distance, d = 2.1 cm = 0.021 m

Using first equation of motion as :

v = u + at

u = 0

Let t is the time taken. Using second equation of motion as :

Since, at = 0.25

So,

t = 0.16 seconds

So, the time taken by the blood to accelerate is 0.16 seconds.    

the answer is b, have negligible mass

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.