Go Back   Physics Help Forum > High School and Pre-University Physics Help > Kinematics and Dynamics

Kinematics and Dynamics Kinematics and Dynamics Physics Help Forum

Reply
 
LinkBack Thread Tools Display Modes
Old Oct 10th 2017, 08:59 AM   #1
Junior Member
 
Join Date: Oct 2017
Posts: 1
Help with practice exam

I have an exam coming up and I don't even know where to begin with this problem. Any help is appreciated


A teacher rides in an elevator that moves upwards at a constant velocity and holds a set keys 1.00m above the
floor of the elevator. After 2.00 seconds of moving upwards from the ground level of the science building, the
teacher releases the keys from their hand. Relative to the ground level of the building, he keys strike the floor of the
elevator at the exact height as where they were released.
(a) [7 pts] Qualitatively sketch, on the same graph, the vertical position (height) of both the keys and the elevator
as a function of time starting from the ground level until some time after the keys hit the floor. Indicate which
curve corresponds to the elevator and which corresponds to the keys. Label the point when the keys are
released.
(b) [4 pts] Describe the motion of the keys and the motion of the elevator shown in your position (height) vs. time
graph in part (a).
(c) [8 pts] Calculate the velocity of the elevator.
(d) [6 pts] Now consider the elevator as traveling downwards at the same constant speed found in part (c). The
keys are again released 1.00m above the floor of the elevator. What is the difference in height (relative to
ground level) between where the keys are released and where they hit the floor of the elevator?
(e) Bonus: [5 pts] Sketch the vertical position (height) of both the keys and the elevator as a function of time
during the downward motion described
mdavies23 is offline   Reply With Quote
Old Oct 11th 2017, 06:31 PM   #2
Senior Member
 
skeeter's Avatar
 
Join Date: Aug 2008
Posts: 110
keys position & elevator floor position

both height in meters vs time in seconds
Attached Thumbnails
Help with practice exam-elev_keys_prob.jpg  
skeeter is offline   Reply With Quote
Old Oct 19th 2017, 10:35 AM   #3
Junior Member
 
Join Date: Jul 2017
Posts: 6
Originally Posted by mdavies23 View Post
I have an exam coming up and I don't even know where to begin with this problem. Any help is appreciated


A teacher rides in an elevator that moves upwards at a constant velocity and holds a set keys 1.00m above the
floor of the elevator. After 2.00 seconds of moving upwards from the ground level of the science building, the
teacher releases the keys from their hand. Relative to the ground level of the building, he keys strike the floor of the
elevator at the exact height as where they were released.
(a) [7 pts] Qualitatively sketch, on the same graph, the vertical position (height) of both the keys and the elevator
as a function of time starting from the ground level until some time after the keys hit the floor. Indicate which
curve corresponds to the elevator and which corresponds to the keys. Label the point when the keys are
released.
(b) [4 pts] Describe the motion of the keys and the motion of the elevator shown in your position (height) vs. time
graph in part (a).
(c) [8 pts] Calculate the velocity of the elevator.
(d) [6 pts] Now consider the elevator as traveling downwards at the same constant speed found in part (c). The
keys are again released 1.00m above the floor of the elevator. What is the difference in height (relative to
ground level) between where the keys are released and where they hit the floor of the elevator?
(e) Bonus: [5 pts] Sketch the vertical position (height) of both the keys and the elevator as a function of time
during the downward motion described
What needs to be noticed that due to the constant speed of both keys and elevator, relative gravity force on keys over the elevator remains sand as they were not moving.
Let us know whether you can proceed with the given solution (graph) by member above.

.
..
...
Be patient, TEX will load, eventually...
__________________
.
..
...
Be patient, TEX will load, eventually...
zemozamster is offline   Reply With Quote
Reply

  Physics Help Forum > High School and Pre-University Physics Help > Kinematics and Dynamics

Tags
exam, kinematics, practice



Thread Tools
Display Modes


Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
Physics Practice Exercises p75213 Kinematics and Dynamics 0 Jul 4th 2010 10:03 PM
Pre-exam problem christina Kinematics and Dynamics 11 Nov 6th 2009 03:57 AM
Mastering Physics practice question Solid8Snake Kinematics and Dynamics 10 Sep 6th 2009 11:28 PM
5 Question from Practice Exam, Please Help Me! Heavyarms2050 Advanced Mechanics 5 May 3rd 2008 07:37 PM


Facebook Twitter Google+ RSS Feed