iron pipes, steel beams, and other steel structures that remain stationary are often found to be magnetized with a distinct polarity. Explain how this can happen. I dont know the answer can someone help :D

Four objects are being tested to see how they are affected by fluid friction. object w has a surface area of 4.5 cm2, object x has a surface area of 2.5 cm2, object y has a surface area of 6.2 cm2, and object z has a surface area of 3 cm2. which object would experience the most fluid friction?

The momentum of an isolated system is conserved a) only in inelastic collisions. b) only in elastic collisions. c) in both elastic and inelastic collisions

Identical marbles are released from the same height on each of the following four frictionless ramps . compare the speed of the marbles at the end of each ramp. explain your reasoning