Mary is at the top of a 25 m steep slide. she is then pushed and starts accelerating at a rate of 4.3 m/s"2. how long will it take her to get to the bottom of the slide?  

Answer

3.4 s

Explanation

The question can be solve by using the 2nd Newton's law of motion.

s = ut + 1/2at²

Before she is pushed, the  initial velocity is zero.

u = 0

Now the equation becomes

s = 0 + 1/2at²

s = 1/2at²

25 = 1/2 × 4.3 × t²

50 = 4.3t²

t² = 50/4.3

  = 11.628

t = √11.628

   = 3.4 s

the answer would be c. motion and direction

i hope this : )

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.