What occurrence defines the end of the protostar phase of a star's life and the start of the main-sequence phase?

How would planets rotate a solar system with two stars?

Moving company uses a machine to raise a 900 Newton refrigerator to the second floor of a building machine consists of a single pulley with a mechanical advantage of 1 how many newtons of input force will it take to raise the refrigerator

What are disadvantages and advantages of parallel circuits

Describe the orbital diagram of an atom with 16 electrons

A ball (mass 0.40 kg) is initially moving to the left at 30 m/s. After hitting the wall, the ball is moving to the right at 20 m/s. What is the impulse of the net force on the ball during its collision with the wall? A) 20 kg.

Objects falling through the air experience a type of friction called air resistance. true or false

How big is a wifi pulse signal coming from your router? A) 10 meters B) 15 meters C) 5-10 meters D) 20-30 meters

Imagine you are in a music concert. What different sounds might you hear? How are these sounds made?

Dose aloe Vera grow in the mesa?

A tradesman sharpens a knife by pushing it against the rim of a grindstone. The 35 cm diameter stone is spinning at 200 rpm and has a mass of 28 kg. The coefficient of kinetic friction between the knife and the stone is 0.20.