A student tries to measure the period of a pendulum that is already swinging left and right. At the moment when the pendulum is fully to the left, she

counts 'One' and starts a stopwatch. She counts successive swings each time

that the pendulum returns to the left. When she counts ‘Ten' she stops the

stopwatch, and sees that it reads 12.0 s.

a. What was her mistake?



b. What is the period of swing of this pendulum?



c. In this particular experiment, explain the likely effect of her reaction time

on her answer.

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

Find the dimensions and area of the largest rectangle that can be inscribed in the upper half of the ellipse. (give your answers in terms of a and b. enter the dimensions as a comma-separated list.)

Avoltaic cell converts chemical energy to