Thorium-229 is a highly radioactive isotope used in the treatment of certain cancers. Use the chart to determine how much thorium would remain after 7,340 years if a sample began at 20 pounds of pure Th-229.

How do the properties of individual elements change when they become part of a compound?

Why is the nirtogen cycle important to the ecosystem?

Why can"t you exert greater force on the pedals of a bicycle if you pill up the handle bars?

What metal has 28 electrons?

Calculate the current in mA through the person, given the voltage of the source to be 120 V and the resistance of the appliance to be 2,552 Ohms.

What does the law of universal gravitation state?

Estimate the smallest possible period of a satellite in a circular orbit around earth. (mass and radius of earth is 5.98 x 1024 kg and 6.37 x 106 m. the universal gravitational constant g = 6.67 x 10-11 n. m2/kg2.)

What happens along a stationary front? a. Cold air rises over warm air. b. The flow of air is neither toward the warm air mass nor toward the cold air mass. c. Air moves so rapidly upward that hurricanes form. d. Wind stops completely.

Which of the following is a vector quantity (a) mass (b) speed (c) time (d) acceleration

A 85-kg astronaut (including spacesuit and equipment) is floating at rest a distance of 11 m from the spaceship when she runs out of oxygen and fuel to power her back to the spaceship. She removes her oxygen tank (3.