Essential University Physics: Volume 1 (3rd Edition)
3rd Edition
ISBN: 9780321993724
Author: Richard Wolfson
Publisher: PEARSON
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Textbook Question
Chapter 4.5, Problem 4.4GI
For each of the following situations, would the cable tension in Example 4.3 be (a) greater than, (b) less than, or (c) equal to the elevator’s weight? (1) elevator starts moving upward, accelerating from rest; (2) elevator decelerates to a stop while moving upward; (3) elevator starts moving downward, accelerating from rest; (4) elevator slows to a stop while moving downward; (5) elevator is moving upward with constant speed
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Problem 5:
In the two cases shown below, a person is standing on a scale in an elevator. The elevators are identical, and the
person weighs 500 N. In both cases the elevator is moving upward, but in Case A it is accelerating upward and in
Case B it is accelerating downward.
A
B
y = 3 m/s
v = 3 m/s
a=2 m/s?
a=2 m/s?
Will the scale reading in Case A be greater than, less than, or the same as the scale reading in Case B?
Explain with a calculation or in words.
A woman weighing 600 N stands on a scale in an elevator. She presses the
button for the BOTTOM floor. Immediately as the elevator starts to accelerate
downward, the scale will read:
Less than 600 N
O 600 N
More than 600 N
O It is impossible to know
Three objects are connected as shown in the figure. The strings and frictionless pulleys have negligible masses. The coefficient of kinetic friction is 0.25 and static friction is 0.30. Block A has a mass of 3 kg and block B has a mass of 4 kg. a) What is the maximum mass block C can have before block B will start to move? b) If block C has a mass of 7 kg. and was 1 m above the ground, how long would it take block C to hit the ground starting from rest?
Chapter 4 Solutions
Essential University Physics: Volume 1 (3rd Edition)
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