Jane told jill that the name sunflower comes from the fact that sunflowers follow the sun in the sky through out the day. jane said that sunflowers actually turn around on their stems to find the sun. to test this idea, jane and jill designed an experiment. they grew a pot of sunflowers outside in natural sunlight, one pot in the house near, but not directly in front of a window, and the final pot inside the house, away from all windows. the girls charted the direction of the sunflower heads throughout the day. all other growing conditions were the same: soil, water, pot size. the girls could not regulate the outdoor temperature, but since it was spring, the day and night temperatures were pretty close to the indoor temperature. which is an appropriate hypothesis for this experiment? a) sunflowers will only grow in natural light.

b) sunflowers grown indoors will bend toward a source of natural light.

c) sunflower heads turn to follow the location of the sun, both indoors and out.

d) sunflowers grown away from natural light will not be as tall as sunflowers grown outdoors.

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

Visualize the problem and identify special cases first examine the problem by drawing a picture and visualizing the motion. apply newton's 2nd law, ∑f⃗ =ma⃗ , to each body in your mind. don't worry about which quantities are given. think about the forces on each body: how are these consistent with the direction of the acceleration for that body? can you think of any special cases that you can solve quickly now and use to test your understanding later? one special case in this problem is if m2=0, in which case block 1 would simply fall freely under the acceleration of gravity: a⃗ 1=−gj^.

How much energy will be transferred to your eardrum while listening to this sound for 1.0 min?