Which of the following is an example of a chemical change?

melting a stick of butter

dissolving salt in water

using magnesium to displace hydrogen gas from water

Which are complete descriptions of the momentum of an object? Circle all that apply. a. 2.0 kg/s b. 7.2 kg•m/s, right c. 6.1 kg•m/s2, down d. 4.2 m/s, east e. 1.9 kg•m/s, west f. 2.3 kg•m/s

Is it possible to add heat to water and not have the temperature increase? Why or why not?

Which best describes the movement of a fluid during convection? A. Warm & cool fluids rise B. Warm & fluids sink C. Warm fluid rises & cool fluid sinks D. Warm fluid sinks & cool fluid rises

In what direction does your brain see light as traveling when it reflects off an object? A. in a straight line B. in a wavy line C. in an S-shaped line D. in a curved line

Which of the following statements proves that scientific knowledge changed due to the discovery of the fossil of a hadrosaur in North Dakota? Hadrosaurs were better runners than earlier thought.

Newtons second law of motion the acceleration of an object equals the net force acting on the object divided by the objects?

An empty train car of mass 2.0 x 104kg coasts along at 10 m/s. A 3000-kg boulder is suddenly dropped vertically into the car. Find the speed of the car immediately after the boulder is dropped in.

Measuring which physical property is most likely to produce the most precise results when trying to identify a substance? luster hardness density viscosity

How is current transferred from the moving armature to the rest of the circuit in an alternating current generator?

There are two types of waves, mechanical and electromagnetic. Microwaves, infrared, and radio was are examples of electromagnetic waves. Which statement is true about the speed of an electromagnetic wave? A) It is not affected by changes in media.