Aperson on a sled coasts down a hill and then goes over a slight rise with speed 2.7 m/s. the top of the rise can be modeled as a circle with a radius 4.1 m. the sled and occupant have a combined mass of 110 kg. if the coefficient of friction between the snow and the sled is 0.10, what friction force is exerted on the sled by the snow as the sled goes over the top of the rise?
it would be super if you could explain how/why you came to your answer as well.

An object is located 30.0 cm from a concave mirror. the focal length is 15.0 c,. what is the image distance? a. 30.0 cm b. -10 cm c. 10.0 cm d. -30.0 cm

The ability to make things happen is also called a. heat b. force c. matter d. energy

Auniform electric field exists in the region between two oppositely charged plane parallel plates separated by a distance of 1.60 cm . a proton is released from rest at the surface of the positively charged plate and strikes the surface of the opposite plate in a time interval of 3.20×10-6 s. 1-find the magnitude of the electric field. use 1.60×10-19c for the magnitude of the charge on an electron and 1.67×10-27kg for the mass of a proton 2-find the speed of the proton when it strikes the negatively charged plate