When a strip of zinc metal is added to a test tube of hydrochloric acid, the liquid forms bubbles, and the test tube feels hot. the bubbles are a result of the formation of hydrogen gas. what does the hot test tube indicate? a. the reaction releases heat. b. hydrogen gas absorbs heat. c. the reaction absorbs heat. d. a chemical change has been reversed.

Calculate the mass of an object that has a momentum of 100kg x m/sec and velocity of 4 m/sec

Point charges q1=+2.00μc and q2=−2.00μc are placed at adjacent corners of a square for which the length of each side is 1.50 cm . point a is at the center of the square, and point b is at the empty corner closest to q2. take the electric potential to be zero at a distance far from both charges. part a what is the electric potential at point a due to q1 and q2? express your answer with the appropriate units.

The gun from the crime scene shows tool marks where the serial numbers are ground off. there are also tool marks on the bullets left behind. what information can the tool marks on the bullets and gun provide about the crime? what type of evidence does this information provide, individual or class?