Una piedra de amolar al reducir su velocidad angular desde 1500 rpm hasta 800 rpm lograr 700 revoluciones. calcular: a) la desaceleración de la piedra b) el tiempo que requiere para esta disminución de velocidad c) si la velocidad continua reduciendo a la misma velocidad ¿cuánto tiempo más se requiere para quedar en reposo? resp. a) -2rad / s² b) 36,65s c) 41,9s

An object weigh 40n in air ,weigh 20n when submerged in water,and 30n when submerged in a liquid of unknown liquid density.what is the density of unknown of liquid?

A2.00-m long piano wire with a mass per unit length of 12.0 g/m is under a tension of 8.00 kn. what is the frequency of the fundamental mode of vibration of this wire?

Consider a uniformly charged ring in the xy plane, centered at the origin. the ring has radius a and positive charge qdistributed evenly along its circumference. a)what is the direction of the electric field at any point on the z axis? . b)what is the magnitude of the electric field along the positive z axis? use k in your answer, where k=14πϵ0. d)the ball will oscillate along the z axis between z=d and z=−d in simple harmonic motion. what will be the angular frequency ω of these oscillations? use the approximation d≪a to simplify your calculation; that is, assume that d2+a2≈a2. express your answer in terms of given charges, dimensions, and constants