At sea level, where g=9.80 m/s^2, a pendulum has a period of 1.000s. When you take it to the top of a mountain, its period is 0.9990s. What is g at the top of the mountain? (Keep 4 significant figures.) (Unit=m/s^2)

The energy released by a chemical reaction can be measured using a calorimeter. when barium hydroxide octahydrate crystals are reacted with dry ammonium chloride inside of a coffee cup calorimeter, the temperature of the 18.00 g of water in the calorimeter decreases from 30.0°c to 8.0°c. the equation for calculating energy absorbed or released by a reaction is: where q is the energy released or absorbed, m is the mass of water in the calorimeter, cp is the specific heat of water, and δt is the observed temperature change. if the specific heat of liquid water is 4.19 j/g·°c, how much energy was absorbed by the reaction?

What was the first instrument to ever record an earthquake?

Which system of units is used by only a small number of countries in the world, including the u.s.