Concept explainers
(a)
The force that the table exerts on box A if box B weighs
Answer to Problem 61QAP
The force exerted by table on box A is
Explanation of Solution
Given:
Box A weighs
Box B weighs
Pulley and rope are massless.
Formula Used:
Calculation:
The forces acting on Box A are the tension in the rope, the force due to gravity, and the force the table exerts on box A (also known as the normal force).
The tension in the rope is equal to the weight of box B when box B is at rest.
If the weight of box B is larger than the weight of box A, both boxes start to move-box A moves up, while box B moves down.
Free-body diagram of box A:
If box A remains at rest, then
If box B weighs
Conclusion:
The force that table exerts on box A if box B weighs
(b)
The force that the table exerts on box A if box B weighs
Answer to Problem 61QAP
The force exerted by table on box A is
Explanation of Solution
Given info:
Box A weighs
Box B weighs
Pulley and rope are massless.
Formula Used:
Calculation:
The forces acting on Box A are the tension in the rope, the force due to gravity, and the force the table exerts on box A (also known as the normal force).
The tension in the rope is equal to the weight of box B when box B is at rest.
If the weight of box B is larger than the weight of box A, both boxes start to move-box A moves up, while box B moves down.
Free-body diagram of box A:
If box A remains at rest, then
If box B weighs
Conclusion:
The force that table exerts on box A if box B weighs
(c)
The force that the table exerts on box A if box B weighs
Answer to Problem 61QAP
The force that table exerts on box A if box B weighs
Explanation of Solution
Given:
Box A weighs
Box B weighs
Pulley and rope are massless.
Formula Used:
Calculation:
The forces acting on Box A are the tension in the rope, the force due to gravity, and the force the table exerts on box A (also known as the normal force).
The tension in the rope is equal to the weight of box B when box B is at rest.
If the weight of box B is larger than the weight of box A, both boxes start to move-box A moves up, while box B moves down.
.
Free-body diagram of box A:
If box A remains at rest, then
If box B weighs more than box A, then we would expect box B to fall down and lift box A off
The table.
Since box A is no longer touching the table, the normal goes to
Conclusion:
The force that table exerts on box A if box B weighs
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Chapter 4 Solutions
College Physics Volume 2
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