Directions:

Please answer the following questions by choosing the answer by the use of the "radio buttons." After finishing with the questions click the "submit answers" button to submit your answers to the server. Use the "constants and formulas" to assist you in answering the questions. Please enter your name before submitting the answers to the questions.

Constants and Formulas:

1. Using a pulley system a worker does 1920 J of work to life a crate from one floor to the next in a warehouse. The force is exerted through a distance of 40 m on the rope of the pulley system. How much force was used to life the crate?

(a) 35 N

(b) 48 N

(c) 40 N

(d) 43.5 N

2. A force of 60 N us needed to push a crate weighing 200 N across a waxed floor. How much work is required to push the crate 15 m.

(a) 755 J

(b) 800 J

(c) 932 J

(d) 900 J

3. The daily food intake of a man is 3000 Cal. Suppose that the man's working efficiency is 10 percent. (That is, 10 percent of the food energy can be converted into useful work.) The man works by lifting 10-kg boxes from a floor onto a shelf that is 2 m high. How many boxes can he lift per day?

(a) 6800 Boxes

(b) 6407 Boxes

(c) 7234 Boxes

(d) 5613 Boxes

4. A machine produces a force of 40 N through a distance of 100 m in 5.0 s. What is the power of the machine in kilowatts?

(a) 1.2 kW

(b) .67 kW

(c) .74 kW

(d) .80 kW

5. An electron with a mass of 9.1 * 10 ^{-31} kg moves through a vacuum with a speed of 2.5 * 10 ^{7} m/s. Find the electron's kinetic energy.

(a) 5.7 * 10^{-16} J

(b) 2.8 * 10^{-16} J

(c) 1.1 * 10^{-23} J

(d) 2.6 * 10^{-13} J