How are mixtures and pure substances different

Aparticle travels in a circular orbit of radius 21 m. its speed is changing at a rate of 23.1 m/s2 at an instant when its speed is 37.2 m/s. what is the magnitude of the acceleration (in m/s? ) of the particle?

Blank liquids and gases exert a buoyant force on objects placed in them

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