a buyer can purchase 70 screwdrivers ten 4-inch length twelve 6 inch length twenty 8-inch length are needed. how many heavy 24-i
1 answer:
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Answer:
See explaination
Explanation:
Some of the Important Observation used in Entity Relational Diagram.
1. A Chemist can be involved one project or many projects
2. A project can hire just one or many chemists.
3. A chemist can lead over one or many projects
4. A project can have only one project leader chemist.
5. A project can be done in 1 or many laboratories.
6. A laboratory can host 0 or 1 projects.
7. A laboratory can have 1 or many equipments.
8. An Equipment can be in 1 or 0 laboratories.
9. A chemist can have 0 or many types of equipments.
10. An Equipment can have 0 or 1 chemist at a time
Notations:
PK=Primary Key:
A primary key, also called a primary keyword, is a key in a relational database that is unique for each record. It is a unique identifier, such as a driver license number, telephone number
FK=Foreign Key:
A foreign key is a column or group of columns in a relational database table that provides a link between data in two tables. It acts as a cross-reference between tables because it references the primary key of another table, thereby establishing a link between them
Composite key:
A composite key is a combination of two or more columns in a table that can be used to uniquely identify each row in the table when the columns are combined uniqueness is guaranteed, but when it is taken individually it does not guarantee uniqueness
Answer:
Explanation:
Soil bearing pressure=
Since we're given pressure of 2500 psf and load of 45000 pounds
The area=
Therefore, the smallest area of safe footings should not be less than
Answer:
a) , b)
, c)
Explanation:
a) The deceleration experimented by the commuter train in the first 2.5 miles is:
The time required to travel is:
b) The commuter train must stop when it reaches the station to receive passengers. Hence, speed of train must be .
c) The final constant deceleration is: