Coulombs Law Problems Gravity vs electric force The

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Coulomb’s Law Problems

Coulomb’s Law Problems

Gravity vs. electric force The electron and proton of a hydrogen atom are separated,

Gravity vs. electric force The electron and proton of a hydrogen atom are separated, on average, by a distance of about 5. 3 x 10 -11 m. Find the magnitudes of the electric force and the gravitational force that each particle exerts on the other. me = 9. 109 x 10 -31 kg mp = 1. 673 x 10 -27 kg e = 1. 60 x 10 -19 C k = 8. 99 x 109 Nm 2/C 2 ANSWER: Fe = 8. 2 x 10 -8 N, Fg = 3. 6 x 10 -47 N

Large electric force Calculate the force between a +1 C and -1 C object

Large electric force Calculate the force between a +1 C and -1 C object if they are placed 1. 0 km away from each other. ANSWER: 9000 N

Hydrogen atom – Bohr model Calculate the speed of an electron in a circular

Hydrogen atom – Bohr model Calculate the speed of an electron in a circular orbit around a proton if the radius of the atom is 5. 29 x 10 -11 m me = 9. 109 x 10 -31 kg mp = 1. 673 x 10 -27 kg e = 1. 60 x 10 -19 C k = 8. 99 x 109 Nm 2/C 2 ANSWER: 2. 18 x 106 m/s

If there are multiple point charges, the resultant force on one particle is the

If there are multiple point charges, the resultant force on one particle is the vector sum of the individual forces on that charge. PRINCIPLE OF SUPERPOSITION

Three charges on a line Find the force on particle 1. 2 -4. 0μC

Three charges on a line Find the force on particle 1. 2 -4. 0μC ANSWER: +5. 7 N 0. 2 m 1 +3. 0 μC 0. 15 m 3 -7. 0 μC

Three charges in a plane Find the force on particle 1. 2 -6. 0

Three charges in a plane Find the force on particle 1. 2 -6. 0 μC 0. 15 m 73 o ANSWER: 23 N @ 24 o 1 +4. 0 μC 0. 1 m 3 -5. 0 μC

Two 1. 1 g balloons are suspended from 2. 0 m long strings and

Two 1. 1 g balloons are suspended from 2. 0 m long strings and hung from the ceiling. They are then rubbed 10 times with animal fur to impart an identical charge Q to each balloon. The balloons repel each other and each string is observed to make an angle of 15° with the vertical. Determine the electric force of repulsion, the charge on each balloon, and the quantity of electrons transferred to each balloon as a result of 10 rubs with animal fur.