Two identical batteries, each with an emf of 18 V and an internal resistance of 1 , are wired in parallel by connecting their positive terminals together and connecting their negative terminals together. The combination is then wired across a 4 resistor. The potential difference across the 4 resistor is:

When an object is heated it contracts. a. true b. false

Karen is running forward at a speed of 9 m/s. she tosses her sweaty headband backward at a speed of 20 m/s. the speed of the headband, to the nearest whole number relative to a stationary observer watching karen

Aparticle moves in the xy plane with constant acceleration. at time zero, the particle is at x = 6 m, y = 8.5 m, and has velocity ~vo = (9 m/s) ˆı + (−2.5 m/s) ˆ . the acceleration is given by ~a = (4.5 m/s 2 ) ˆı + (3 m/s 2 ) ˆ . what is the x component of velocity after 3.5 s? answer in units of m/s.