Two boys on skates push off from each other. the 40 kg boy moves to the left at 10 m/s. if the other boy moves to the right at 8 m/s, what is his mass?

The difference between a red shift and a blue shift has to do with wavelength frequency. t or f

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.

Which substance partical has negligible massand travels around outsidethe nucleus