A 73.0 kg father and his 45.0 kg son are sitting on opposite sides of a 4.00 m seesaw at the playground. The pivot point is fixed at the mid-
point of the board. Where must the father position himself to horizon-
tally balance the seesaw if his son sits at the end of the board?

Asmall electric heater, immersed in 80g of water in a calorimeter of 40j/k raises the temperature from 10.5 degree celsius to 25 degree celsius in 12 minutes. using the same apparatus with 50g of oil instead of water, it is found that the temperature of oil rises from 7 degree celsius to 27 degree celsius in 10 minutes. find specific heat capacity of the oil.