In the early 1900s, robert millikan used small charged droplets of oil, suspended in an electric field, to make the first quantitative measurements of the electron’s charge. a 0.68-μm-diameter droplet of oil, having a charge of +e, is suspended in midair between two horizontal plates of a parallel-plate capacitor. the upward electric force on the droplet is exactly balanced by the downward force of gravity. the oil has a density of 860 kg/m3, and the capacitor plates are 4.0 mm apart. part a what must the potential difference between the plates be to hold the droplet in equilibrium?

Player kicks a soccer ball from ground level and sends it flying at an angle of 30 degrees at a speed of 26 m/s. what is the horizontal velocity component of the ball to the nearest tenth of a m/s?

The roller coaster from problem #1 then tops a second hill at 15.0 m/s, how high is the second hill? 91.5 m 79.2 m 80.0 m 68.5 m

The second largest public utility in the nation is the sole provider of electricity in 32 counties of southern florida. to meet the monthly demand for electricity in these counties, which is given by the inverse demand function p = 1,200 – 4q, the utility company has set up two electric generating facilities: q1 kilowatts are produced at facility 1, and q2 kilowatts are produced at facility 2 (so q = q1 + q2). the costs of producing electricity at each facility are given by c1(q1) = 8,000 + 6q12 and c2(q2) = 6,000 + 3q22, respectively. determine the profit-maximizing amounts of electricity to produce at the two facilities, the optimal price, and the utility company’s profit