A large rock is motionless on a flat sidewalk. Which statement best explains why the rock remains motionless? There are no forces acting on the rock.

The sidewalk exerts an unbalanced force on the rock.

The only force acting on the rock is directed at the sidewalk.

The forces acting on the rock are all balanced.

Matches the chemical name of each oxide of phosphorus to its chemical formula

How much energy is made when a pice of wood burns. how do you know

Balance and in which category does it fit in? single or double displacement or synthesis or decomposition? (a) k2 o → k + o2 (b) na + i2 → nai (c) cu(no3 )2 + naoh → cu(oh)2 + nano3 (d) kclo3 → kcl + o2 (e) ca(no3 )2 + hbr → cabr2 + hno3 (f) sn(oh)2 → sno + h2 o (g) p4 + n2 o → p4 o6 + n2 (h) fe + al2 (so4 )3 → feso4 + al (i) alcl3 + na2 co3 → al2 (co3 )3 + nacl (j) c3 h6 + o2 → co2 + h2 o