What is on the other side of a black hole

What is the measure of how much matter is in an object and that can be measured using a balance? a. height b. volume c. weight d. mass

Select the correct answer. what does the process of natural selection involve?

Aspring is used to stop a 50-kg package which is moving down a 20º incline. the spring has a constant k = 30 kn/m and is held by cables so that it is initially compressed 50 mm. knowing that the velocity of the package is 2 m/s when it is 8 m from the spring and neglecting friction, determine the maximum additional deformation of the spring in bringing the package to rest.