What causes interstellar dust and gas to start to contract and form a protostar? 1) the shockwave from a supernova 2) nearby black hole 3) an increase in the solar wind 4) nuclear fusion

Anybody wanna ? (picture included? )

1. jay fills a wagon with sand (about 20 kg) and pulls it with a rope 30 m along the beach. he holds the rope 25° above the horizontal. the rope exerts a 20-n tension force on the wagon. how much work does the rope do on the wagon?

Estimate the change in the gibbs energy and molar gibbs energy of 1.0dm3 of octane when the pressure acting on it is increased from 1.0 atm to 100 atm. the mass density of octane is 0.703 g cm−3