What measures the weight of the air above a certain point.

Sound is a disturbance that travels through a medium as a

What is the weight of a feather (mass = 0.0001 kg) that floats through earth's and the moon's atmospheres?

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.