Two point charges 30 nc and -40 nc are held at the origin and at x 0.72 m, respectively
particle q = 42 uc is released from rest at x 0.28 m. if the initial acceleration of the particle he
magnitude of 1 x 10^5 m/s, what is its mass?

Along wire of diameter 1 mm is submerged in an oil bath of temperature ∞ 31°c. the wire has an electrical resistance per unit length of 0.01 ω/m. if a current of 103 a flows through the wire and the convection coefficient is 500 w/m2·k, what is the steady-state temperature of the wire? from the time the current is applied, how long does it take for the wire to reach a temperature that is within 1°c of the steady-state value? the properties of the wire are 8000 kg/m3, 500 j/kg·k, and 20 w/m·k.