# Engineering Mechanics Statics 13th edition

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1.6 GENERAL PROCEDURE FOR ANALYSIS

15

PROBLEMS

1

1–1. Round off the following numbers to three significant figures: (a) 58 342 m, (b) 68.534 s, (c) 2553 N, and (d) 7555 kg.
1–2. Wood has a density of 4.70 slug > ft3. What is its density expressed in SI units?
1–3. Represent each of the following combinations of
units in the correct SI form: (a) kN>ms (b) Mg>mN, and
(c) MN>(kg # ms).
*1–4. Represent each of the following combinations of units in the correct SI form using an appropriate prefix:
(a) m>ms, (b) mkm (c) ks>mg, and (d) km # mN.
1–5. Represent each of the following quantities in the correct SI form using an appropriate prefix: (a) 0.000 431 kg, (b) 35.3(103) N, (c) 0.005 32 km.
1–6. If a car is traveling at 55 mi>h, determine its speed in kilometers per hour and meters per second.
1–7. The pascal (Pa) is actually a very small unit of pressure. To show this, convert 1 Pa = 1 N>m2 to lb>ft2. Atmosphere pressure at sea level is 14.7 lb>in2. How many pascals is this?
*1–8. The specific weight (wt.>vol) of brass is 520 lb>ft3. Determine its density (mass>vol) in SI units. Use an appropriate prefix.
1–9. A rocket has a mass 250(103) slugs on earth. Specify (a) its mass in SI units, and (b) its weight in SI units. If the rocket is on the moon, where the acceleration due to gravity is gm = 5.30 ft>s2, determine to three significant figures (c) its weight in SI units, and (d) its mass in SI units.
1–10. Evaluate each of the following to three significant figures and express each answer in SI units using an appropriate prefix: (a) (0.631 Mm) > (8.60 kg)2, (b) (35 mm)2 (48 kg)3.
1–11. Evaluate each of the following to three significant figures and express each answer in SI units using an appropriate prefix: (a) 354 mg(45 km)>(0.0356 kN), (b) (0.004 53 Mg) (201 ms), (c) 435 MN>23.2 mm.

*1–12. Convert each of the following and express the answer using an appropriate prefix: (a) 175 lb>ft3 to
kN>m3, (b) 6 ft>h to mm>s, and (c) 835 lb # ft to kN # m.
1–13. Convert each of the following to three significant
figures. (a) 20 lb # ft to N # m, (b) 450 lb>ft3 to kN>m3, and
(c) 15 ft>h to mm>s.
1–14. Evaluate each of the following and express with an appropriate prefix: (a) (430 kg)2, (b) (0.002 mg)2, and (c) (230 m)3.
1–15. Determine the mass of an object that has a weight of (a) 20 mN, (b) 150 kN, (c) 60 MN. Express the answer to three significant figures.
*1–16. What is the weight in newtons of an object that has a mass of: (a) 10 kg, (b) 0.5 g, (c) 4.50 Mg? Express the result to three significant figures. Use an appropriate prefix.
1–17. If an object has a mass of 40 slugs, determine its mass in kilograms.
1–18. Using the SI system of units, show that Eq. 1–2 is a dimensionally homogeneous equation which gives F in newtons. Determine to three significant figures the gravitational force acting between two spheres that are touching each other. The mass of each sphere is 200 kg and the radius is 300 mm.
1–19. Water has a density of 1.94 slug>ft3. What is the density expressed in SI units? Express the answer to three significant figures.
*1–20. Two particles have a mass of 8 kg and 12 kg, respectively. If they are 800 mm apart, determine the force of gravity acting between them. Compare this result with the weight of each particle.
1–21. If a man weighs 155 lb on earth, specify (a) his mass in slugs, (b) his mass in kilograms, and (c) his weight in newtons. If the man is on the moon, where the acceleration due to gravity is gm = 5.30 ft>s2, determine (d) his weight in pounds, and (e) his mass in kilograms. 