500 cm3 of water is to be heated from room temperature (28°c) to 100°c In order to prepare hot cup of coffee
What to the minimum heat required?
How Long with It takes to heat
the water with a 1000w heating
coil which has a
heating efficiency
of 70% ?​

there are no contact forces mentioned on the list of choices that you've provided.

the kind of relationship between atmospheric  density and altitude is inverse relationship. this means a surge in either will cut the other factor. density is mass per unit volume, it is hard to compute with only altitude 1,291 kilometers given. also, we could also use temperature and pressure to resolve density but they are not delivered.