A helicopters speed decreases from 60 m/s to 25 m/s in 5 second. What is the acceleration of this helicopter

How have the competing explanations' experiments on atoms affected the development of the atomic model?

Aplayground merry-go-round has a radius of 4.6 m and a moment of inertia of 200 kg-m2 and turns with negligible friction about a vertical axle through its center. a child applies a 26.0 n force tangentially to the edge of the merry-go-round for 15.0 seconds. if the merry-go-round is initially at rest, how much work did the child do on the merry-go-round?

Why do astronauts in the space shuttle weigh less?