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Dyna (Assign1 5-8)

This document contains solutions to physics problems involving constant acceleration, rectilinear motion governed by an equation, and the motion of a ladder sliding along a floor with one end contacting a vertical wall. The initial velocity problem is solved using kinematic equations for acceleration. The rectilinear motion problem shows that the acceleration is equal to minus two times the displacement. For the sliding ladder problem, the velocity of the upper end is shown to equal the negative of the lower end's velocity times the tangent of the angle between the ladder and the wall.

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Cris Vincent Rivera Sedanto
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3K views3 pages

Dyna (Assign1 5-8)

This document contains solutions to physics problems involving constant acceleration, rectilinear motion governed by an equation, and the motion of a ladder sliding along a floor with one end contacting a vertical wall. The initial velocity problem is solved using kinematic equations for acceleration. The rectilinear motion problem shows that the acceleration is equal to minus two times the displacement. For the sliding ladder problem, the velocity of the upper end is shown to equal the negative of the lower end's velocity times the tangent of the angle between the ladder and the wall.

Uploaded by

Cris Vincent Rivera Sedanto
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
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9-3.14.

A train moving with constant acceleration travels 24 ft during the 10


th
sec of its motion and
18 ft during the 12
th
sec of its motion. Find its initial velocity.
Solution:
S1oth = 24 ft @ t = 9 sec to 10 sec
S12th = 18 ft @ t = 11 sec to 12 sec

@ S1oth:


S9-10

(eq. 1)

@ S12th:


S11-12

(eq. 2)

Using the eq. 1 & 2:







9-3.16. An auto A is moving at 20 fps and accelerating at 5 fps
2
to overtake an auto B which is 382 ft
ahead. It auto B is moving at 60 fps and decelerating at 3 fps
2
, how soon will A pass B?
Solution:
@ Auto A: @ Auto B:

(eq. 2)

(eq. 2)
Subtract eq. 2 from eq. 1:





9-3.18. The rectilinear motion of a particle is governed by the equation s = r sin t where r and
are constants. Show that the acceleration is a = -
2
s.
Solution:

;
;


;
;


Since
Therefore:







9-3.20. A ladder of length L moves with its ends in contact with a vertical wall and a horizontal
floor. If a ladder starts from a vertical position and its lower end A moves along the floor with a
constant velocity vA, show that the velocity of the upper end B is vB = vA tan where is the angle
between the ladder and the wall. What does the minus sign mean? Is it physically possible for the
upper end B to remain in contact with the wall throughout the entire motion? Explain.
Solution:


But


Therefore:


When = 90,

, which is impossible.

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