Une barre homogène OB de masse m= 10kg est articulée en O contre un mur ng dessous. Elle est maintenue en équilibre à l'aide d'un fil inextensible et de masse négligeable.
B
Donnée : mes O AC= 90°; OB=20A; OB=OC= 2m.
1.
Définis le système et représente les forces extérieures qui lui sont appliquées.
2. Détermine:
2.1. La mesure de l'angle OCA;
2.2. Le poids de la barre;
2.3. La valeur de la tension du fil et celle de la réaction du mur.​

Which statements describe the relationship between science and society? check all that apply. science is influenced by the needs of society. science and society are independent. science seeks ways to meet the needs of society. scientists find new ways to address societal concerns. scientists improve existing products.

Search coils and credit cards. one practical way to measure magnetic field strength uses a small, closely wound coil called a search coil. the coil is initially held with its plane perpendicular to a magnetic field. the coil is then either quickly rotated a quarter-turn about a diameter or quickly pulled out of the field. (a) derive the equation relating the total charge q that flows through a search coil to the magnetic-field magnitude b. the search coil has n turns, each with area a, and the flux through the coil is decreased from its initial maximum value to zero in a time ∆t. the resistance of the coil is r, and the total charge is q = i∆t, where i is the average current induced by the change in flux. (b) in a credit card reader, the magnetic strip on the back of a credit card is rapidly “swiped” past a coil within the reader. explain, using the same ideas that underlie the operation of a search coil, how the reader can decode the information stored in the pattern of magnetization on the strip. (c) is it necessary that the credit card be “swiped” through the reader at exactly the right speed? why or why not?

For which pair of objects would adding the same a