A moving walkway has a speed of 0.5 m/s to the east. A stationary observer sees a man walking on the walkway with a velocity of 0.8 m/s to the east.
What is the man's velocity relative to the moving walkway?

What is the orbital period of a spacecraft in a low orbit near the surface of mars? the radius of mars is 3.4×106m.

Name two kinds of practical electric pumps.

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.