Question

Each experiment requires us to measure the force on the wire, however we do not have a direct way to do so. Using our knowledge of Newton’s Laws, we can infer the magnitude of the force. Question 4. Assuming the current and magnetic field are as shown in Fig. 2, use the right-hand rule to determine the direction of the predicted force of the magnet on the wire.

[INEED HELP WITH NUMBER 5. I ALREADY DID NUMBER 4]

rigure . Lurrent walance apparatus. Adupled from Pasco instruction manual. As shown in Fig. 2, the cantilever arm holds the PC board so that the lowermost run of wire, the stretch that is immersed in the magnetic field, is horizontal. The magnet assembly contains a number of permanent magnets arranged so that their magnetic field is horizontal across the slot, so the field is perpendicular to the current. Magnet Assembly Figure 2. Expanded view of magnet assembly and current (the circle indicates the current is out of the page).

Question 5. (cont’d from Q4) According to Newton’s third law and your answer to Question 4, what must the force of the wire on the magnet be? (Make sure you understand the difference between what Question 4 and 5 are asking.)

Answer 1

The force on magnet due to wire is equal to the force on wire due to magnetic field. This is in accordance with Newton third law which states that for every action there is equal and opposite reaction. A pair of action reaction force act always on any kind of physical interaction, either in contact or non-contact cases.

The answer to question 5 is same as answer 4, but the direction of force only change, becomes opposite.