Which of the following is a star early in its life?

A. Protostar

B. Main sequence star

C. White dwarf

D. Red giant

What is the difference between frequency and speed?

Select the correct answer. Which phenomenon occurs when a wave encounters a non-transmitting barrier? A refraction of the wave with a different wave speed B. reflection of the wave with a different wavelength C.

Which feedback triggers the production of hormones?

You are driving in the left lane on a multi-lane expressway, and are moving a bit faster than other traffic. a speeding car comes up behind you. you should a: stay in the left lane, and continue at the same speed you were at before.

Sally stands 3 meters from the fulcrum. Reggie weighs 800 N and stands 2 meters from the fulcrum. The see saw is balanced. How much does sally weight?

Changing the direction of current will or will not affect the strength of an electromagnet

A swimming pool has the dimensions of 10 meters, 5 meters, and 1 meter. What is the pool's volume? 50 m 50 m3 50 m2 25 m3

A child pushes horizontally on a box of mass m which moves with constant speed v across a horizontal floor. The coefficient of friction between the box and the floor is μ. At what rate does the child do work on the box?

What two qauntities must be known to calculate the density of a sample of matter

An element's atomic number is 38. How many protons would an atom of this element have?