Automatic sliding doors The first automatic sliding doors were described by Hero of Alexandria almost 2000 years ago. The doors were moved by hanging containers that were filled with water. Modern sliding doors open or close automatically. They are equiped with sensors that detect the proximity of a person and an electromic circuit that processes the signals from the sensors and drives the electomotor-based system that moves the doors. The sensors typically emit pulses of infrared light or ultrasound and detect the reflected pulses. By measuring the delay between emitted and received pulses, the system can determine the distance to the object from which the pulse was reflected. The whole system must be carefully designed to ensure safe and accurate functioning. Designers of such doors take into account several variables such as typical walking speeds of people and their dimensions. Let’s try to learn more about automatic sliding doors by analyzing the motion of a single-side automatic sliding door when a person is walking through the door. Figure 2.30 shows the position-versus-time graph of the motion of the edge of the door (marked with a red cross in the photo) from the moment the door starts opening to when the door is closed while a person walks toward and through the door. The doors are adjusted to start opening when a person is 2.0 m away. A person is walking at constant speed of 1.15 m/s toward and through the sliding door. How far from the door is the person when the door starts closing? a. 2.3 m b. 4.3 m c. 6.3 m d. 8.3m
Automatic sliding doors The first automatic sliding doors were described by Hero of Alexandria almost 2000 years ago. The doors were moved by hanging containers that were filled with water. Modern sliding doors open or close automatically. They are equiped with sensors that detect the proximity of a person and an electromic circuit that processes the signals from the sensors and drives the electomotor-based system that moves the doors. The sensors typically emit pulses of infrared light or ultrasound and detect the reflected pulses. By measuring the delay between emitted and received pulses, the system can determine the distance to the object from which the pulse was reflected. The whole system must be carefully designed to ensure safe and accurate functioning. Designers of such doors take into account several variables such as typical walking speeds of people and their dimensions. Let’s try to learn more about automatic sliding doors by analyzing the motion of a single-side automatic sliding door when a person is walking through the door. Figure 2.30 shows the position-versus-time graph of the motion of the edge of the door (marked with a red cross in the photo) from the moment the door starts opening to when the door is closed while a person walks toward and through the door. The doors are adjusted to start opening when a person is 2.0 m away. A person is walking at constant speed of 1.15 m/s toward and through the sliding door. How far from the door is the person when the door starts closing? a. 2.3 m b. 4.3 m c. 6.3 m d. 8.3m
Automatic sliding doors The first automatic sliding doors were described by Hero of Alexandria almost 2000 years ago. The doors were moved by hanging containers that were filled with water. Modern sliding doors open or close automatically. They are equiped with sensors that detect the proximity of a person and an electromic circuit that processes the signals from the sensors and drives the electomotor-based system that moves the doors. The sensors typically emit pulses of infrared light or ultrasound and detect the reflected pulses. By measuring the delay between emitted and received pulses, the system can determine the distance to the object from which the pulse was reflected. The whole system must be carefully designed to ensure safe and accurate functioning. Designers of such doors take into account several variables such as typical walking speeds of people and their dimensions.
Let’s try to learn more about automatic sliding doors by analyzing the motion of a single-side automatic sliding door when a person is walking through the door. Figure 2.30 shows the position-versus-time graph of the motion of the edge of the door (marked with a red cross in the photo) from the moment the door starts opening to when the door is closed while a person walks toward and through the door. The doors are adjusted to start opening when a person is 2.0 m away.
A person is walking at constant speed of 1.15 m/s toward and through the sliding door. How far from the door is the person when the door starts closing?
You want to fabricate a soft microfluidic chip like the one below. How would you go about
fabricating this chip knowing that you are targeting a channel with a square cross-sectional
profile of 200 μm by 200 μm. What materials and steps would you use and why? Disregard the
process to form the inlet and outlet.
Square Cross Section
1. What are the key steps involved in the fabrication of a semiconductor device.
2. You are hired by a chip manufacturing company, and you are asked to prepare a silicon wafer
with the pattern below. Describe the process you would use.
High Aspect
Ratio
Trenches
Undoped Si Wafer
P-doped Si
3. You would like to deposit material within a high aspect ratio trench. What approach would you
use and why?
4. A person is setting up a small clean room space to carry out an outreach activity to educate high
school students about patterning using photolithography. They obtained a positive photoresist, a
used spin coater, a high energy light lamp for exposure and ordered a plastic transparency mask
with a pattern on it to reduce cost. Upon trying this set up multiple times they find that the full
resist gets developed, and they are unable to transfer the pattern onto the resist. Help them
troubleshoot and find out why pattern of transfer has not been successful.
5. You are given a composite…
Two complex values are z1=8 + 8i, z2=15 + 7 i. z1∗ and z2∗ are the complex conjugate values.
Any complex value can be expessed in the form of a+bi=reiθ. Find r and θ for (z1-z∗2)/z1+z2∗. Find r and θ for (z1−z2∗)z1z2∗ Please show all steps
Chapter 2 Solutions
College Physics: Explore And Apply, Volume 2 (2nd Edition)
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