Which scenario describes a change in velocity?
an apple that is hanging from the tree.
a car at rest at a traffic light.
a person on an amusement ride that is spinning in a circle.
a plane traveling at 800 mph at cruising altitude.

What’s #16 asking and how do i solve it?

At 20∘c, the hole in an aluminum ring is 2.800 cm in diameter. you need to slip this ring over a steel shaft that has a room-temperature diameter of 2.804 cm . 1. to what common temperature should the ring and the shaft be heated so that the ring will just fit onto the shaft? coefficients of linear thermal expansion of steel and aluminum are 12×10−6 k−1 and23×10−6 k−1 respectively.

What quantity do units represent in value