An electron orbits a proton in a hydrogen atom at a speed of 2.9 x 10^6 m/s. If it takes the electron 1.6 x 10^-15 s to complete one orbit, what is the circumference of the atom?

Assuming weightless pulleys and 100% efficiency, what is the minimum input force required to lift a 120 n weight using a single fixed pulley?

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 10.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.90 m/s; (b) he is then lifted at the constant speed of 4.90 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 68.0 kg rescue by the force lifting him during each stage?

When conducting an investigation to determine which type of fertilizer produces the most flowers on a plant, which variable would be graphed on the x-axis once you collected the data? a. type of fertilizer b. amount of flowers c. amount of water d. number of days that the plants grew