An isotope decreased to one fourth its original amount in 18 months. What is the half life of this radioactive isotope?

Think about the pencil-dropping activity that you did in the introduction. What did the target finally look like?

How do you calculate the work done when lifting an object?

How do many coal-powered factories change the environment? by causing increased erosion by releasing pesticides into the air by releasing oil into the ocean by causing acid rain

How many minutes each day should a middle school age student be involved in physical activity?

Two crates, of mass 75kg and 110 kg are in contact and at rest on a horizontal surface. a 730 N force is exerted on a 75kg crate. if the coefficient of kinetic friction is 0.

A flask that weighs 345.8 g is filled with 225 mL of carbon tetrachloride. The weight of the flask and carbon tetrachloride is found to be 703.55 g. From this information, calculate the density of carbon tetrachloride.

Why do people use Earth's motions to determine units of time?

Which of the following could be described as "Energy cannot be created or destroyed, only converted into other forms"? A. Rebound-crumple theorem B. Impulse-momentum theorem C. Law of conservation of energy D. Law of conservation of momentum

Which one of the following statements is true? 1. Burning coal contributes to sulfur aerosols in the stratosphere; these sulfur aerosols have moderated global warming. 2.

A diver on a diving board is undergoing simple harmonic motion. Her mass is 55.0 kg and the period of her motion is 0.800 s. The next diver is a male whose period of simple harmonic oscillation is 1.05 s.