Phzx

(ii)
(b) gives
(c) Gravity is unvarying and equal to mg. n is not constant; it is zero at A and not zero at B. Therefore, is alike not constant.
(d) applied to Figure 7.9 gives

EVALUATE: In the absence of friction, the speed of the rock at point B would be As the rock slides through point B, the convening string is greater than the cant over of the rock.


Figure 7.9
7.14. secernate: aim the information given in the problem with to find k. thus
SET UP: x is the amount the spring is stretched. When the weight is hung from the spring,
EXECUTE: The spring could be either stretched 9.52 cm or compressed 9.52 cm. If it were stretched, the heart length of the spring would be If it were compressed, the total length of the spring would be
EVALUATE: To stretch or compress the spring 9.52 cm requires a force
7.29.



IDENTIFY: Since the force is constant, use
SET UP: For both displacements, the burster of the friction force is opposite to the displacement and
EXECUTE: (a) When the deem moves to the left, the friction force is to the right, and the work is
(b) The friction force is now to the left, and the work is again
(c)
(d) The net work done by friction for the round trip is not zero, and friction is not a conservative force.
EVALUATE: The direction of the friction force faces on the motion of the object. For the gravity force, which is conservative, the force does not depend on the motion of the object.
7.45.IDENTIFY: The mechanical faculty of the scroll coaster is conserved since there is no friction with the track. We must also apply Newtons second law for the aeronaut motion.
SET UP: For part (a), apply conservation of energy to the motion from point A to point B: with delimit and conservation of energy becomes or In part (b), the free-body plat for the roller coaster car at point B is shown in Figure 7.45. gives where Solving for the normal force gives...If you want to bushel a full essay, order it on our website: Ordercustompaper.com



If you want to get a full essay, wisit our page: write my paper