How and why may a theory be discarded

Two cars are facing each other from opposite ends of a 500m long road. Car A begins travelling at a constant speed of 20m/s. At the same moment, Car B begins travelling toward Car A at a constant speed of 16m/s.

Kepler's first law states that planets orbit the Sun in a path called a (n) A) area B) Period C) ellipse D) parabola.

Zinc reacts with aqueous sulfuric acid to form hydrogen gas. in an experiment, 125 ml of wet h2 is collected over water at 27 degc and a barometric pressure of 753 torr. the vapor pressure of water at 27 degc is 26.74 torr.

All compounds are positively charged true or false

What is the formula for lithium and chlorine?

Planetary nebulae are characterized by an emission spectrum consisting of Balmer (hydrogen) emission lines and a pair of strong emission lines at 4959˚A and 5007˚A that were quite mysterious when first seen.

What is the mass of oxygen in an oxygen tank at 20 C if the tank has a volume of 0.20 m3 and the oxygen pressure in the tank is 4.0 105 N/m2 (mass of one mole of one mole of oxygen is 16 g and the universal gas constant is 8.

What is one advantage infrared astronomy has over visible light astronomy?

A 60-kg runner raises his center of mass approximately 0.5 m with each step. Although his leg muscles act as a spring, recapturing the energy each time his feet touch down, there's an average 10% loss with each compression.

Two cyclists who weigh the same and have identical bicycles ride up the same mountain, both starting at the same time. Joe rides straight up the mountain, and Bob rides up the longer road that has a lower grade. Joe gets to the top before Bob.