A ball is tossed straight up from the surface of a small, spherical asteroid with no atmosphere. The ball rises to a height equal to the asteroid's radius and then falls straight down toward the surface of the asteroid. The acceleration of the ball at the top of its path is:

a. at its maximum value for the ball's flight.

b. equal to the acceleration at the surface of the asteroid.

c. equal to one-half the acceleration at the surface of the asteroid.

d. equal to one-fourth the acceleration at the surface of the asteroid.

(d) equal to one-fourth the acceleration at the surface of the asteroid.

Explanation:

From Newton's gravitational law, force between two objects (planet) is directly proportional to the product of their masses and inversely proportional to the square of their distance apart.

Case 1: when the ball rises to a height equal to the asteroid's radius

height, h = r

Case 2: when the ball rises to a height equal to the asteroid's radius and falls straight down toward the surface of the asteroid.

At top of its path, total height is 2r.

h = 2r

Therefore, the acceleration of the ball at the top of its path is equal to one-fourth the acceleration at the surface of the asteroid.

Option "d"

hi,

what occurs during a solar eclipse?

there are small tides across earth.

the moon is between earth and the sun.

p.s. im not sure if the first answer is correct because during a solar ecliphse there are spring tides and i dont know if they are the same.

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.