What term defines the specific amount of time required for half of a radioactive substance to become stable?

a. half-life

b. decay phase

c. decay period

d. a gamma second

Sources of error in archimedes principle

Mahmood is lifting a bag of cement. He uses 5 N of force to lift the bag 20 meters. If Mahmood uses a machine to decrease the distance to 10 meters, he will ___.

Match each term to its definition. element compound ion isotopes cation anion A. substance made of just one type of atoms B. a positively charged ion resulting from the loss of electrons C.

A derived unit is a combination of fundamental units. Which of the following is an example of a derived unit? a) centimeter (used to measure distance) b) gram (used to measure mass) c) cubic centimeter (used to measure volume)

According to the big bang theory, the universe was once a very and hostile place. a. cold b. restless c. hot

An ice rink is 200 feet long and 85 feet wide. The four corners of the rink are rounded to a radius of 24 feet. What is the surface area of the rink? Round the answer to the nearest square foot.

Which statement is correct about gasoline when it is burned? Heat energy is created by the gasoline. The total energy of the gasoline decreases. Chemical energy in the gasoline is destroyed. Chemical energy is transformed into heat energy.

The tilt of the Earth's axis of rotation changes over a period of 41,000 years. Which of these statements best predicts a long term effect of the changes in the tilt of the Earth's axis of rotation? a. The Earth's climate would change. b.

What do keratinized cells form?

Explain why Planck's introduction of quantization accounted for the properties of black-body radiation.