Which would you expect to have the greatest amount of friction?
a- a smooth surface on a smooth surface
b-a smooth surface on a rough surface
c-a rough surface and air
d-a rough surface on a rough surface

Debbie places two shopping carts in a cart corral she pushes the first cart which then pushes a second cart what force is being exerted

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length of a column of water 1.00 km high for a temperature increase of 1.00ºc. note that this calculation is only approximate because ocean warming is not uniform with depth. (answer in ×10^{-3} −3 m)

Una carga puntual de 3 x 10-6 c se coloca a 12 cm de una segunda carga puntual de - 1,5 x 10-6 c. calcular la magnitud fuerza eléctrica entre las cargas