A large insulator sphere of radius R has uniform charge distribution inside, and the total charge is Q. If you cut a small sphere of radius r from the the large sphere, The charge inside your small sphere is equal to:

The charge inside the small sphere is .

Explanation:

Since, charge is uniformly distributed throughout the sphere.

Therefore, charge density of sphere is,   .

Charge on sphere of radius r is,

Putting value of in above equation.

We get ,

Hence, this is the required solution.

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s