determine if the pennies are made of pure copper by comparing the density with that of the pure copper

Consider the nuclear equation below. 239/94 pu—-> x+ 4/2 he. what is x?

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?

How does climate change cause the ocean's thermohaline current to slow down?