Which of the following are not clues that a chemical reaction has taken place?

A. Steam

B. Formation of a gas

C. Change in color

D. Constant temperature

How can you calculate the number of electrons in an atom

A simply supported wood beam of rectangular cross section and span length 1.2 m carries a concentrated load P at midspan in addition to its own weight (see gure). The cross section has width 140 mm and height 240 mm.

A 190-N box is placed on an inclined plane that makes a 20.0° angle with the horizontal. Find the component of the weight force parallel to the plane's surface.

A ball is dropped from the top of a cliff. By the time it reaches the ground, all the energy in its gravitational potential energy store has been transferred into its kinetic energy store.

You push on a door and it opens. Explain what happens in terms of action-reaction forces.

Does the acceleration of a falling body change or is it constant

What can cause sediment to form on land? Only mechanical weathering rocks Only biological weathering rocks Any kind of weathering or rocks Melting of rock in the core

The speed of a car is decreasing uniformly from 35 m/s to 15 m/s in 4 s the magnitude of the car's acceleration is

An object that has kinetic energy must what?

A student measures the length and width of a rectangle to be 40.7 cm and 0.599 cm, respectively. Wanting to find the area (in cm2) of this rectangle, the student multiplies on a calculator and obtains a result of 24.3793.