A 500. gram sample of nickle-63 has a half-life of 100. years and has decayed for 500. years. How much of the original 500. gram sample remains?

87.1 grams

574 grams

16,000 grams

15.6 grams

How is our solar system organized?

Two soccer players, Mia and Alice, are running as Alice passes the ball to Mia. Mia is running due north with a speed of 6.00 m/s. The velocity of the ball relative to Mia is 5.00 m/s in a direction 30.0 east of south.

Classify the reaction that occurred between the iron and oxygen. The reactions that are possible are synthesis, decomposition, single replacement, double replacement, combustion, oxidation, or reduction

A uniform wire of resistance R is cut into three equal lengtsh. one of these is formed into circle and connected between the others two. what is the resistance between opposite end?

A gas that exists in outer space is made of

In which is momentum conserved: an elastic collision or an inelastic collision?

List the types of radiation in order from least to most damaging.

Which of the following statements best describes the current state of understanding regarding the apparent acceleration of the expansion of the universe?

Should young people be allowed to do extreme sports? (give me two reasons why) 1. Opinion: 2. Reason why: 3. Reason why:

A light ray is incident on a reflecting surface. If the light ray makes a "35°" angle with respect to the normal to the surface, what is the exact angle (in degrees) made by the reflected ray relative to the normal?