In the last 20 years geologists have begun measuring accumulation of helium (he) in some minerals because these minerals can retain he at temperatures up 100-200°c. the "date" gives a time when the material cooled below the temperature where the helium began to be retained, which is related to the depth of the material. where do you think the he comes from that allows this technique to work?

Aspecial electronic sensor is embedded in the seat of a car that takes riders around a circular loop-the-loop ride at an amusement park. the sensor measures the magnitude of the normal force that the seat exerts on a rider. the loop-the-loop ride is in the vertical plane and its radius is 23 m. sitting on the seat before the ride starts, a rider is level and stationary, and the electronic sensor reads 740 n. at the top of the loop, the rider is upside down and moving, and the sensor reads 370 n. what is the speed of the rider at the top of the loop?

When you turn on a battery-operated device, an electrical circuit is

He viscosities of several liquids are being compared. all the liquids are poured down a slope with equal path lengths. the liquid with the highest viscosity will