Directions: Follow the instructions in each Part below to complete the assignment.

Part A

Directions: Answer each of the following questions.

1. The Mars Climate Orbiter crash was explained as being caused by a mix-up between metric and imperial units. The computer was programmed to work with pound weight (lbF) instead of newton. Given that the weight of 1 kg is equivalent to the weight of 2.2 pounds (lb), or 2.2 lbF, and that the weight of 1 kg (or 2.2 lbF) is 9.8 N:

a. Find the force in newtons of the weight of 1.0 lbF. b. If the thrusters to put the craft into orbit were meant to use a value in N but used the same value in lb F, would they slow the craft more or less? c. Analysis of the mission failure showed the thrusters force was 4.45 times too large, is the failure correctly explained by a unit mix-up?

2. Usain Bolt holds the world record for the 100 m sprint with a time of 9.58 s. His top speed is about 43.45 kmh^-1.

a. What is Usain's average speed in...ms^-1...kmh^-1? b. Why was his average speed less than his top speed? c. How long would the race take if Usain had run at his top speed for the entire race?

3. It takes 40 N for Tamara to push a chair slowly and steadily across the carpet. She pushes the chair 4 m from one side of the room to the other.

a. How much work did Tamara do? b. What happened to the work she did? c. How could Tamar reduce the amount of work she is doing?

Part B

Directions: Answer each of the following questions.

1. Which of the following is true?

a. The earth revolves around the sun once a year.

b. The earth revolves around the sun for about 365 1/4 days.

c. Earth's orbit or ecliptic is strictly an ellipse with the sun at one focus.

d. The speed of the earth varies slightly on account of the eccentricity of the orbit.

e. All of these

2. The mean solar day is about __________ than the sidereal day.

3. Short time intervals can be measured accurately by indirect methods that make use of tuning __________.

4. The world land speed record is 763.0 mi/h, set on October 15, 1997, by Andy Green in the jet-engine car Thrust SS C. Express this speed in meters per second.

5. What is the quantity which Physics deals?

6. The accuracy of a precision clock is checked at regular intervals with _______________.

7. 1 meter = ________ in.

8. 1 yard = __________ meter.

9. What is used for the record of official time?

10. Any particular object is composed of a definite quantity of matter determined by _______________.

11. What is the basis for measurements of time-based on?

12. The tallest tree in the United States is Founder's Tree, a redwood in northern California. Its height is 364 ft. and its girth is 47.1 ft. Express these dimensions in meters.

13. 1 kilometer = _________ mile.

14. In scientific and engineering work, it is usually desired to measure the duration of an interval of time rather than to determine the correct time at a certain instant. What is it?

15. Which of the following is false about the precision clock?

a. Its accuracy is checked at regular intervals with a meridian telescope.

b. They are the least accurate timekeepers available.

c. Precision clocks are designed and constructed with the utmost care.

d. Precision clocks are kept in constant-temperature rooms to insure uniform operation.

e. It is used to record the official time.