Hello!! I hope someone can help me with this question. If you can explain it to me along with the CORRECT answer, and only one of you do that, I will give you brainliest! How long must a pendulum be for a swing from one side to the other to take exactly 1s here on the surface of the earth? Use 9.81m/s^2 for acceleration due to gravity.

Rules for brainliest:
-Correct answer
-if one says how to do it and another does not, the one who explained will receive brainliest
-there has to be two answers for me to give brainliest

stay positive and hope you can help! xoxo

A175 g lump of molten lead at its melting point (327 c) is placed into 55.0 g of water at 20.0 c. the specific heat of lead is 130.j/kg c and the hf of lead is 20,400 j/kg. when the lead and the water have reached equilibrium, what is the temperature of the mixture?

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?

The two stars in a certain binary star system move in circular orbits. the first star, alpha, has an orbital speed of 36 km/s. the second star, beta, has an orbital speed of 12 km/s. the orbital period is 137 d. a) what is the mass of the star alpha? b) what is the mass of the star beta?