Ethan visited the Crosby Observatory at the Orlando Science Center. The observatory houses the largest refracting telescope available to the public in Florida. One night, he observed several stars that all seemed to be equally bright. However, one of the astronomers explained that each star actually had a different absolute brightness. What information do you need to calculate a star's absolute brightness? Choose the two that apply. Group of answer choices

An exothermic reaction is conducted in an insulated calorimeter filled with water. the calorimeter is then sealed so that there is no heat exchanged between the contents of the container and the surrounding air. which of the following statements is true about the reaction?

One or more substances changing into one or more substances is an example of a

Plz mark brainliest 30 points1) find the momentum of a 12 kg snowball that is rolling with a velocity of 9 m/s.2) an 8 ball with a mass of .5 kg is sitting at rest. it is hit by the cue ball (1 kg) traveling at 2.5 m/s. if the cue ball is at rest after the collision, how fast is the 8 ball traveling after the collision? 3) two football players are running toward each other. if the offensive player is 75 kg and is running 8 m/s, how fast must the 60 kg defensive player run in order for the two players to hit and stop?