There are ways to reduce the friction between an object and a surface. For instance, if you wanted to reduce the friction between a piece of furniture and a floor, you could wax the floor to make it smoother. You could also attach wheels to the furniture. Imagine the bed in the previous example was on wheels. Would it be hard to move? The friction between a bed on wheels and the floor is much smaller than the friction between the same bed without wheels and the floor. The friction resisting the bed’s motion is smaller when the bed is on wheels, so moving this bed across the floor requires a smaller force. Look again at your corrected free-body diagram for a motionless bed. In order for the bed to start moving forward, what needs to be greater, your sister’s pushing force or the friction?

While studying chemical reactions and conservation of matter, sarah's class conducted a variety of experiments. sarah and her lab partner found the mass of a wax candle and placed the candle in a flask. the students lit the candle and let it burn to completion. all that was left was wax and charred candle wick. per their teacher's instructions, the students found the mass of the products. their data can be seen in the data table. formulate a hypothesis the students could test to explain why the experiment did not support the law of conservation of matter. a) the students could repeat the experiment using different candles; there might have been a flaw in the candle. b) the experiment should be repeatable. the students should run several trials and then take an average of the after mass in each trial. c) the students should have someone in the class check their measurement skills as they repeat the experiment. they may have made an error using the balance. d) the students should burn the candle in a container that has some type of lid so that any gas that is a product of the reaction can be contained and massed. submit

Adisk with a radius of r is oriented with its normal unit vector at an angle q with respect to a uniform electric field. which of the following would result in an increase in the electric flux through the disk? check all that apply? a. increasing the area of the disk b. decreasing the given orientation angle of the disk c. decreasing the strength of the electric field d. increasing the given orientation angle of the disk, but not exceeding an angle of 90

The largest observatory complex in the world is on mauna kea, the tallest mountain on earth. what are some factors astronomers consider when selecting an observatory site? don’t forget practical ones. should astronomers, for example, consider building an observatory on denali (mount mckinley) or mount everest?