Explain! i don’t understand how to find the answer.

a metal bolt with a mass of 8.50 x 10^-2kg and a temperature of 85.0°c is placed in a container of water. the mass of the water is 0.150 kg, and its temperature is 25.0°c. what is the specific heat capacity of the bolt if the final temperature of the bolt and water is 28.4°c? (specific heat of water= 4186 j/kg·°c)

An ideal otto cycle has a compression ratio of 8. at the beginning of the compression process, air is at 95 kpa and 27°c, and 750 kj/kg of heat is transferred to air during the constant-volume heat-addition process. assuming constant specific heats at room temperature, determine (a) the pressure and temperature at the end of the heat-addition process, (b) the net work output, (c) the thermal efficiency, and (d) the mean effective pressure for the cycle. (4390 kpa, 1730 k; 423 kj/kg; 56.4%; 534 kpa)