Please help me find the distance of 1.42x10^9 km in light years. Include the steps!

Which simple machine is not part of this compound machine? a. lever b. pulley c. inclined plane d. wheel and axle

Astudent creates a model of a closed ecosystem by filling a glass tank half full with water, then adding 10 snails and two small aquatic plants. the next day, all the snails are dead. what is the most likely cause of their death?

What is the weight of a feather (mass = 0.0001 kg) that floats through earth's and the moon's atmospheres?