Kepler improved the copernican model of the universe by adding : string theory
elliptical orbits
pulsars
epicycles on epicycles

Aweight lifter raises a 1600 n barbell to a height of 2.0 meters. how much work was done? w = fd question 6 options: 3000 joules 30 joules 320 joules 3200 joules

What are two different ways you could find the value of a? explain these methods.

Scientific models are based on current knowledge, which can limit their effectiveness when new discoveries are made.