Question

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

Answer 1

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

Answer 2

`mass=10.53kg`

Step-by-step explanation:

The momentum is defined by the following expression:

`p=mv`

where
`p` is the momentum,
`m` is the mass and
`v` 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
`m` in the last equation:

`m=(p)/(v)`

and we know the values for the momentum
`p` and the speed
`v`:

`p=20kgm/s`

`v=1.9m/s`

substituting these values to find the mass:

`m=(20kgm/s)/(1.9m/s)`

`m=10.53kg`

The mass of the dog is 10.53kg