Achild pulls a sled up a snow covered hill. the child does 405 j of work on the sled. if the child walks 15m up the hill, how large of a force must the child exert?

What structural formula represents 4 electrons shared between two atoms?

Jenny wants to test the electrical conductivity of two substances dissolved in water. she is preparing the containers for the experiment. which factor is most important for her to control? a) volumes of the solutions b) appearance of the solutions c) temperatures of the solutions d) concentrations of the solutions

Aheavy piece of hanging sculpture is suspended by a90-cm-long, 5.0 g steel wire. when the wind blows hard, the wire hums at its fundamental frequency of 80hz. what is the mass of the sculpture?