In soap box car races, the cars are boxes with wheels. they begin at rest at the top of a hill, and at the start of the race they all begin rolling down the hill. the soap box car that reaches the bottom of the hill first is the winner. you have entered a soap box car race where the rule is that all the wheels and cars must have equal mass. since you have taken physics, you know that it is worse to have wheels with spokes (where the mass is mostly on the rim) rather than solid wheels becausea.) the solid wheels are easier to paint. b.) the solid wheels have a higher rotational mass or moment of inertia and therefore will retain more rotational energy. c.) given the same torque, the wheels with spokes have a higher rotational mass or moment of inertia and therefore will have a greater angular acceleration. d.) given the same torque, the wheels with spokes have a higher rotational mass or moment of inertia and therefore will have a smaller angular acceleration. e.) given the same amount of energy, too small a fraction is converted into rotational kinetic energy of the wheels.

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

Describe cytokinesis in plants and animals. in animals: in plants.

Review multiple-concept example 7 in this chapter as an aid in solving this problem. in a fast-pitch softball game the pitcher is impressive to watch, as she delivers a pitch by rapidly whirling her arm around so that the ball in her hand moves in a circle. in one instance, the radius of the circle is 0.626 m. at one point on this circle, the ball has an angular acceleration of 66.1 rad/s2 and an angular speed of 12.6 rad/s. (a) find the magnitude of the total acceleration (centripetal plus tangential) of the ball. (b) determine the angle of the total acceleration relative to the radial direction.