Explain whether or not there must be an unbalanced net force acting on any moving object

1. Trial and error is discouraged in science because it wastes time. True False 2. Conduction is the movement of energy from one substance to another by direct contact. True False

Which of the following is the flow of electrons through a wire or a conductor

Sarah's mom takes a parkway to work. It takes her 30 minutes to travel from mile marker 88 where she enters to her exit at mile marker marker 121. What is her average speed?

Explain the origin of the magnitude designation for determining the brightness of stars. Why does it seem to go backward, with smaller numbers indicating brighter stars?

How does the strong nuclear force hold the nucleus of an atom together? a) It overcomes the electrical force of attraction between protons in the nucleus. b) It overcomes the electrical force of repulsion between protons in the nucleus.

A girl runs 20.9 m/s East for 13.7s. How far does she go?

Is it possible to have a weak acid or base?

Why does an object accelerate when falling to earth's surface?

2.5 g of helium at an initial temperature of 300 K interacts thermally with 9.0 g of oxygen at an initial temperature of 620 K.

34. A steam engine operates between 300K and 600K, the maximum possible efficiency of this engine is a. 100% b. 75% c. 50% d. 25%