SOLVE STEP BY STEP IN DIGITAL FORMAT A steel bar is taken out of a furnace at a temperature of 900 °C and allowed to quench in air for 60 minutes, reaching a temperature of 50 °C. If the environment is at 20 °C and th rate of change of the temperature of the bar with respect to time is proportional to the temperature difference between the bar and the environment, determine: a) the proportionality constant b) the time it takes for the steel bar to reach 35 °C

The volume V of an ideal gas varies directly with the temperature T and inversely with the pressure P. A cylinder contains oxygen at a temperature of 310 degrees K and a pressure of 18 atmospheres in a volume of 120 liters. Find the pressure if the volume is decreased to 95 liters and the temperature is increased to 330 degrees K. I am struggling with this problem and have been for ages... please help.

The electrostatic force between two electrically charged particles varies inversely as the square of the distance between them. If two charged particles are 1.3 meters apart and the electrostatic force between them is 2 Newtons (a standard unit of force in Physics), what is (A) the constant of proportionality k , and (B) what is the force between them if the distance is changed to 2.3 meters

Hooke's law states that the distance a spring stretches varies directly as the weight on the spring. Let d represent the distance (in inches) the spring stretches, let wrepresent the weight (in pounds) on the spring, and let k be the constant of proportionality. Write an equation that relates d to w. d =     A weight of 50 pounds stretches a spring 8 inches.     Use the equation that relates d to w and the known information to find k. k =   How far (in inches) will a weight of 120 pounds stretch the spring? in