A 'SawStop' table saw quickly stops the rotation of the saw blade when it comes in contact with a capacitive object (such as a finger), to prevent accidents. A carpenter pushes a piece of plywood through the table saw at a speed of 5 cm/s. The stopping mechanism is triggered (don't worry the carpenter is safe!). (A)The circular saw blade has a radius 12 cm and rotates at 4,000 rpm. If the rotation of the saw stops 2 ms (0.002 s) after contact with the blade, what is the angular acceleration as the blade slows down, assuming that the acceleration is constant (it will be very large and damage parts of the saw in the process).
(B) What angle will the saw blade rotate through as it comes to stop?
(C) If the blade stops rotating in 2.0 ms, the piece of wood would only travel 0.1 mm, about the thickness of a piece of paper, before the saw blade has stopped rotating (just a scratch)!

Dinate system, and a charge q = - 2.00 nc is placed s2 10 n> c. (a) what is the change in electric potential energy when the dipole moment of a molecule changes its orientation with respect to es from parallel to perpendicular? (b) at what absolute temperature t is the average translational kinetic energy 32 kt of a molecule equal to the change in potential energy calculated in part(: abovethistemperature,thermalagitationprevents the dipoles from aligning with the electric field.) placed in a uniform electric field e with magnitude 1.6 * 6 on the positive x-axis at x = 4.00 cm. (a) if a third charge q3 = +6.00 nc is now placed at the point x = 4.00 cm, y = 3.00 cm, find the x- and y-components of the total force exerted on this charge by the other two. (b) find the magnitude and direction of figure p21.62 ll uu 21.55 . torque on a dipole. an electric dipole with dipole moment ps is in a uniform external electric field es. (a) find the orientations of the dipole for which the torque on the dipole is zero. (b) which of the orientations in part (a) is stable, and which is unstable? (hint: consider a small rotation away from the equi- librium position and see what happens.) (c) show that for the stable orientation in part (b), the dipole’s own electric field tends to oppose the external field. 21.62 ..

5g of ammonium nitrate was dissolved in 60g of water in an insulated container. the temperature at the start of the reaction was 23.0°c and at the end it was 19.0°c. calculate the energy absorbed by the reaction.

Explain the comparisons between nature and packingtown that appears on pages 81 and 82 answer