Which statement describes the forces acting on a pencil resting on a desk? A.
The force of gravity pushes up on the pencil, while the desk provides a balanced force pushing down.

B.
The force of gravity pushes down on the pencil, while the desk provides a balanced force pushing up.

C.
The force of gravity pushes up on the pencil, while the desk provides an unbalanced force pushing down.

D.
The force of gravity pushes down on the pencil, while the desk provides an unbalanced force pushing up.

The energy released by a chemical reaction can be measured using a calorimeter. when barium hydroxide octahydrate crystals are reacted with dry ammonium chloride inside of a coffee cup calorimeter, the temperature of the 18.00 g of water in the calorimeter decreases from 30.0°c to 8.0°c. the equation for calculating energy absorbed or released by a reaction is: where q is the energy released or absorbed, m is the mass of water in the calorimeter, cp is the specific heat of water, and δt is the observed temperature change. if the specific heat of liquid water is 4.19 j/g·°c, how much energy was absorbed by the reaction?

Power can be defined as a. the distance over which work was done. b. how much work can be done in a given time. c. all the work in an given area. d. the energy required to do work.

Astudent creates a model of a closed ecosystem by filling a glass tank half full with water, then adding 10 snails and two small aquatic plants. the next day, all the snails are dead. what is the most likely cause of their death?