Which of the following is the first step in the technological design process? HELP ASAP PLEASE!! due: 11/20/20

A. construct a prototype

B. evaluate the design

C. define a need or problem

D. research existing solutions

Asap and show ! a 14 kg rock starting from rest free falls through a distance of 5.0 m with no air resistance. find the momentum change of the rock caused by its fall and the resulting change in the magnitude of earths velocity. earth mass is 6.0 * 10^24 kg. show your work assuming the rock earth system is closed.

What is the temperature in degrees celsius of a substance with a tempature of 49k

Which of the following are appropriate acceleration units?