HELP PLEASE ASAP Question 5 of 15 Lead-196 has a half-life of 37 minutes. It decays into thallium-196. Suppose a
sample contains 20 atoms of lead-196 and 60 atoms of thallium-196. About
how old is the sample?
A. 74 minutes
O B. 37 minutes
O c. 111 minutes
O D. 148 minutes

An insulated 40 ft^3 rigid tank contains air at 50 psia and 120°f. a valve connected to the tank is now opened, and air is allowed to escape until the pressure inside drops to 25 psia. the air temperature during this process is kept constant by an electric resistance heater placed in the tank. determine the electrical work done during this process.

Where should a carbon monoxide detector be mounted?

Afisherman notices that his boat is moving up and down periodically, owing to waves on the surface of the water. it takes a time of 2.70 s for the boat to travel from its highest point to its lowest, a total distance of 0.700 m. the fisherman sees that the wave crests are spaced a horizontal distance of 6.50 m apart. a. how fast are the waves traveling? b. what is the amplitude a of each wave?