An isotope has a half life of 2 days. After 6 days, how much of the original material is left?

A. 12%

B. 12.5%

C. 30.2%

Explain why the universe must be an isolated system to obey the law of conservation of mass.

An object has a mass of 20 g and a volume of 5 cm3. what is the object's density? 4 g/cm3 100 g/cm3 0.25 g/cm3

How does the value of the electrostatic force vary with the value (how many) of the charges?

A ball is dropped from rest from a Cliff and falls for 3 seconds. Neglecting air resistance, the final velocity of the ball is m/s. (g = - 9.8 m/s2) Enter the answer

A rock has been formed by the accumulation of bits of rocks that were originally formed by the release of heat by magma. How should this rock be classified? igneous rocks sedimentary rocks metamorphic rocks organic rocks

Which organization functions to privide clinics and surgeries i developing nations

What role do convection currents play in oceans and the atmosphere?

What causes density currents to form in the mediterranean sea? a. condensation b. evaporation c. transpiration d. upwelling

How long does it take a car to travel 450 km at 75 km/hr

A free-falling golf ball strikes the ground and exerts a force on it