Ahot metal bar is submerged in a large reservoir of water whose temperature is 75∘f. the temperature of the bar 20s after submersion is 120∘f. after 1min submerged, the temperature has cooled to 100∘f. (a) determine the cooling constant k. k= s−1 (b) what is the differential equation satisfied by the temperature f(t) of the bar? f′(t)= use f for f(t). (c) what is the formula for f(t)? f(t)= (d) determine the temperature of the bar at the moment it is submerged. initial temperature = ∘f