An artist working on a piece of metal in his forging studio plunges the hot metal into oil in order to harden it. the metal piece has a mass of 54 kg and its specific heat is 0.1027 kcal/(kg · °c). he uses 810 kg of oil at 35°c. the specific heat of oil is 0.7167 kcal/(kg · °c). once the metal is immersed in the oil, the temperature reaches an equilibrium value of 39°c. how hot was the forged metal piece just before he plunged it into the oil?

What is the frequency of a light wave with a wavelength of 620nm

Which of the following are guidelines to follow for obtaining accurate observations

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".