Adog running with a speed of 1.9 m/s has a momentum of 20 kg⋅m/s . what is the mass of the dog?

Explanation:

The momentum is defined by the following expression:

where is the momentum, is the mass and is the velocity.

In this case we already have a value for the momentum, and we are looking for the mass, so we clear for in the last equation:

and we know the values for the momentum and the speed :

substituting these values to find the mass:

The mass of the dog is 10.53kg

Momentum = (mass) x (speed)

(20 kg-m/s) = (mass) x (1.9 m/s)

Divide each side by (1.9 m/s) :

Mass = (20 kg-m/s) / (1.9 m/s)

Mass = (20/1.9) (kg-m/s)/(m/s)

Mass = 10.53 kg

it has to be b, about 97 percent.

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.