Find the mass of 250 mL of water. The density of water is 1 g/mL.

Explanation:

The mass of a substance when given the density and volume can be found by using the formula

From the question

volume = 250 mL

density = 1 g/mL

So we have

mass = 250 × 1

We have the final answer as

Hope this helps you

The velocity of the second mass is -0.8*v

Explanation: This is a perfectly inelastic collision, where two objects that collide move together as if they were stuck to each other.

The final velocity in this type of collision is

Vf = (m1*v1 + m2*v2)/(m1 + m2)

Where the "m"'s are the masses of each object, and the v's are the velocities.

Here we know that m1 = m2 = m, v1 = v, Vf = 0.100*v

we want to find the value of v2

0.100*v = (m*v + m*v2)/(2m) = m(v + v2)/(2m) = (v + v2)/2

0,100*v = v/2 + (v2)/2

v(0.100 - 1/2) = (v2)/2

-v*0.400*2 = v2

v2 = -v*0.8

Then we know that the second mass is moving with a velocity of -0.8*v (the minus sign means that this object is moving in the opposite direction with respect to the other object)

One interesting thing in this type of collision is that the kinetic energy does not conserve