301 (F97) Exam #1 Solution

# 301 (F97) Exam #1 Solution -...

This preview shows pages 1–3. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 7########,################y##]#######_#######{####################h####h##5 ####5####5####M#.##############(##A####]#(#######P###x##{###M# ##m####'#*##Q###5#############m######### ## #=##'####'####'####'####'####'####Name #1. [35 points] Block A is resting on top of block B as shown in the diagram at right. The mass of block B is twice that of block A. A. [20 pts] The blocks are moving to the right on a table at constant speed, and block A does not slip relative to block B.# i. In the space provided, draw a separate free-body diagram for each block. Explicitly label the forces as instructed in class. Draw your vectors roughly to scale. ii. If both members of any third law (action/reaction) force pairs appear in the free-body diagrams above, identify them with tick marks as was done in class.#B. [15 pts] While the blocks are moving to the right, a hand pushes horizontally on block B as shown in the diagram at right. Block A does not slip relative to block B.i. What is the direction of the acceleration of block B? Explain your reasoning. Block B is moving in a straight line and slowing down. The change in velocity over a short time interval, and thus the acceleration, is opposite the velocity. Thus the acceleration of block B is to the left. ii. How would the magnitudes of the forces exerted now on block A differ, if at all, with those indentified above in Part A? Explain your reasoning. iii. How does the magnitude of the net force on block A compare to the magnitude of the net force on block B? If the net force on either block is zero, state that explicitly. Explain your reasoning. Since block A does not slip relative to block B, the two blocks move as a unit and have the same velocity and the same acceleration. Using Newtons second law, #o(F,) = #o(F,)net = m#o(a,), since the blocks have the same acceleration, the block with the larger mass has the larger net force. Thus, block B has the larger net force. #2. [35 pts total] Block U is on top of an identical block L. A person pushes horizontally on block U as shown. NOTE: There is no friction between the table and the blocks, however, there is sufficient friction between the blocks that they do not slide relative to one another. A. [6 pts] Draw a free-body diagram for the lower block L. Draw and label the forces as in class to make clear: the object exerting the force the object on which the force acts the type of force (normal, frictional, gravitational, etc.)B. [6 pts] Draw a free-body diagram for the upper block U. Label the forces as above.#C. [6 pts] If both members of any third law force pairs appear in the diagrams for parts A and B, identify both members of each pair....
View Full Document

## This document was uploaded on 10/29/2011 for the course PHSX 301 at MSU Bozeman.

### Page1 / 234

301 (F97) Exam #1 Solution -...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online