Amy gets up from her seat on a train to move closer to the front. just as she begins to walk forward, the train stops at a station. what is the best explanation of what happens to amy?

a. while amy is walking, her body is in motion. when the train stops, because she's not buckled in, amy continues to move forward due to inertia.

b. while amy is walking, her body is in motion. when the train stops, an unbalanced force accelerates her body backward.

c. while amy is walking, her body is in motion, but as the train stops, it exerts a force on amy opposite to the direction she is walking, causing her to stop as well.

d. while amy is walking, she is in motion due to the force of repulsion. when the train stops, she is catapulted forward due to the train's stronger force of attraction.

my best guesses would be d or c, but only from what common sense tells me. answer and explanation, ? guys!

Free runners jump long distances and land on the ground or a wall. how do they apply newton’s second law to lessen the force of impact?

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 ..

Cyclotrons are widely used in nuclear medicine for producing short-lived radioactive isotopes. these cyclotrons typically accelerate h- (the hydride ion, which has one proton and two electrons) to an energy of 5 mev to 20 mev. this ion has a mass very close to that of a proton because the electron mass is negligible—about 1 2000 of the proton’s mass. a typical magnetic field in such cyclotrons is 1.9 t. (a) what is the speed of a 5.0-mev h-? (b) if the h- has energy 5.0 mev and b = 1.9 t, what is the radius of this ion’s circular orbit?