Correct answer only ! a car travels at a constant velocity of 70 mph for one hour. at the second hour, the car’s velocity was 60 mph. at the third hour, the car’s velocity was 80 mph. at what hour was their positive acceleration? at what hour was their negative acceleration? show your work!

Power can be defined as a. the distance over which work was done. b. how much work can be done in a given time. c. all the work in an given area. d. the energy required to do work.

Which component of the earth’s atmosphere is decreased due to photosynthesis?

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.