Dark matter is inferred to exist because: we see lots of dark patches in the sky. it explains how the expansion of the universe can be accelerating. we can observe its gravitational influence on visible matter.

The density of free electrons in gold is $5.90\times 10^{28}electrons/m^{3}$ Find the drift speed of electrons in a gold wire of diameter 2.98 mm when a current of 0.175 A flows through the wire. $17.8\times 10^{-6}m/s$ $4.32\times 10^{-6}m/s$ $15.8\times 10^{-8}m/s$ $2.65\times 10^{-6}m/s$ $3.00\times 10^{8}m/s$

Newton's laws of motior fail: when dealing with extremely low masses. for objects with extremely large masses. when using atomic clocks rather than stopwatches. at speeds significantly less than the speed of light. in helping us understand most of the everyday world.

At night, you should drive at a speed that you can stop: In the distance illuminated ahead With ABS brakes Before you hit anything Quickly

The branch of biomechanics that deals with the aspects of moving systems is known as dynamics. kinetics. mobility. kinematics.

A radioactive substance decays exponentially. A scientist begins with 140 milligrams of a radioactive substance. After 24 hours 70 mg of the substance remains. How many milligrams will remain after 27 hours? $\square $ mg Give your answer accurate to at least one decimal place Question Help: Video

__ are very similar to diodes. none of the above Transistors Resistors all of the above Photovoltaic cells

Which roadway conditions does not cause loss of traction? a) gravel roads b) uneven surfaces C) snow and ice d) none of these

When a forklift is loaded, where is its center of gravity? A. Under the operator B. At the center of the forklift C. Varies based on the combined centers of gravity of the forklift and the load D. At the center of the forks

The net electric force acting on each of the three objects below is sketched as a green arrow. For example if the green arrow points to the left the object feels a net electric force pushing it to the left.If there is no green arrow, the object feels no net electric force. Use this information to assign an electric charge to each object. That is, decide whether each object has a positive electric charge, a negative electric charge, or is neutral. Note for advanced students.there may be more than one correct answer.

Which side of the electromagnetic spectrum has shorter waveiengths? $\square $ Which side of the electromagnetic spectrum has higher energy? $\square $ Which side of the electromagnetic spectrum has higher frequencies? $\square $ blue