Did kepler propose the modern model of the solar system?

Which notation is used to represent an alpha particle? a. b. c. d.

How many neutrons does element x if it’s atomic number is 28 and its mass number is 87

An object with initial temperature 130 ∘ f is submerged in large tank of water whose temperature is 50 ∘ f . find a formula for f ( t ) , the temperature of the object after t minutes, if the cooling constant is k = − 0.2 . remember newton's law of cooling (the rate of change of temperature with respect to time is equal to k times the difference between the temperature of the object and the surrounding temperature) ! : )