I need full solution A projectile is fired from the ground level with a velocity
of 500 ms-1 at 30° to horizon. What is the least speed with which it could be projected in order to
achieve the same horizontal range ? [g = 10m/s2]

1 a

2 b

3 b

4 d

5 d

6 d

explanation:

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.

according to jean piaget, in what stage of cognitive development are children able to understand conservation task?

b. preoperational

just took it