I need some help with this one :)

If 21.2 kcals of energy is released by this reaction, how many kj does the reaction release? (1 cal 4.184 j)

The diagram shows four locations in the electric field of a positive point charge m. at which location is the electric potential the greatest.

The lift raises a car of mass 850 kg to a height of 2.1 m. it uses a force of 8330 n and takes 4 seconds to raise the car. what is the power of the lift?