Question

q2 chemistry: u3l1 coulombs law
teacher:
date:
prepwork part 1: coulombs law practice
use your knowledge of coulombs law to complete the following statements:

1. **according to coulombs law, magnitude of charge and the force between 2 charged objects is

, which means

1. **according to coulombs law, distance between objects and the force between 2 charged objects is

, which means
examine the two scenarios below which each show 2 oppositely
charged objects held at different distances. assume that the
magnitude of each charge remains constant between scenarios.

1. **which scenario shows charges with the greatest attractive

force between them? circle the scenario below.
scenario 1
scenario 2

1. **explain your reasoning from question 3 using coulombs law.

examine each manipulation of a variable below and state the impact on the force between two objects. the first
three have been done for you as examples.
ex 1: the magnitude of one charge is tripled. the force between objects will triple also.
explanation: force and charge are directly proportional, so whatever happens to the magnitude of a
charge, the same will happen to the force.
ex 2: both charges are halved. the force between objects will decrease to a quarter of its original force.
explanation: force and charge are directly proportional - in this case, both charges are halved, so i
need to multiply these together to determine the impact on force. 1/2 × 1/2 = 1/4
practice: for each practice problem below, show your reasoning using annotations.

1. *the magnitude of one charge is quadrupled. the force will
2. **the distance between two charges is quadrupled. the force will
3. *the distance between the charges is decreased to 1/3 of its original distance. the force will
4. the magnitude of one charge is doubled while the distance between charges is also doubled. the force will

Explanation:

Step1: Recall Coulomb's Law formula

Coulomb's Law is given by \( F = k\frac{q_1q_2}{r^2}\), where \(F\) is the force between two charges, \(k\) is the Coulomb's constant, \(q_1\) and \(q_2\) are the magnitudes of the charges, and \(r\) is the distance between them.

Step2: Analyze problem 5

For problem 5, if the magnitude of one charge (\(q_1\) or \(q_2\)) is quadrupled (let's say \(q_1'=4q_1\)), using the formula \(F' = k\frac{q_1'q_2}{r^2}=k\frac{4q_1q_2}{r^2} = 4F\). So the force will quadruple.

Step3: Analyze problem 6

For problem 6, if the distance \(r\) is quadrupled (\(r' = 4r\)), then \(F'=k\frac{q_1q_2}{r'^2}=k\frac{q_1q_2}{(4r)^2}=k\frac{q_1q_2}{16r^2}=\frac{F}{16}\). So the force will decrease to \(\frac{1}{16}\) of its original value.

Step4: Analyze problem 7

For problem 7, if \(r'=\frac{1}{3}r\), then \(F'=k\frac{q_1q_2}{r'^2}=k\frac{q_1q_2}{(\frac{1}{3}r)^2}=k\frac{q_1q_2}{\frac{1}{9}r^2}=9F\). So the force will increase to 9 times its original value.

Step5: Analyze problem 8

For problem 8, if \(q_1' = 2q_1\) and \(r'=2r\), then \(F'=k\frac{q_1'q_2}{r'^2}=k\frac{2q_1q_2}{(2r)^2}=k\frac{2q_1q_2}{4r^2}=\frac{F}{2}\). So the force will decrease to \(\frac{1}{2}\) of its original value.

Answer:

1. quadruple
2. decrease to \(\frac{1}{16}\) of its original value
3. increase to 9 times its original value
4. decrease to \(\frac{1}{2}\) of its original value