10 Problems
January 3, 2020
You should do all of these problems, but at a minimum do: 1, 2, 3, 7, 11, 20, 21, 24, 28, 29. If you find any errors in any of these questions in particular the posted answers, contact Jennifer Kirkey for bonus marks<EMAIL_ADDRESS>You are expected to do these problems as homework. You do not have to hand them in, yet it is possible (likely) that there will be in class work, quizzes and tests that are very similar to these assigned problems.
Problems
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What is the weight in newtons at the surface of the Earth of an object that has a mass of (a) 7.77 kg (b) 0.0333 mg, and (c) 888 Mg? Assume that g = 9.81 m/s2 (Answers a) 76.2 N b) 0.327 mN c) 8.71 MN)
- Represent each of the following combinations of units in the correct SI form a) b) MN/ms b) mg/μN c) kN/(kg•ms) (Answers a) GN/s b) kg/N c) MN/(kg•s) )
- Use standard engineering notation to represent each of the following as a number between 0.1 and 1000 using an appropriate prefix: (a) 45600 kN, (b) 567 x 105 mm, and (c) 0.00345 mg. (Answer: 45.6 MN b) 56.7 km c) 3.45 μg)
- Represent each of the following quantities in the correct SI form using an appropriate prefix: a) 0.000 123 kg b) 34.5(103) N = 34.5 x 103 N c) 0.002 34 km (Answers a) 0.123 g b) 34.5 kN c) 2.34 m )
- Round off the following numbers to three significant figures and use the appropriate prefix: (a) 58322 m, (b) 65.432 s, (c) 3453 N, and (d) 8555 kg. (Answers a) 58300 m = 58.3 km b) 65.4 s c) 3450 N = 3.45 kN d) 8560 kg = 8.56 Mg)
- Convert: (a) 300 lb•ft to N•m b) 600 lb/ ft3 to kN/m3 , (c) 4 ft/h to mm/s. Give your final answer to three significant figures as usual and use the appropriate prefix. (Answer: a) 407 N•m b) 94.3 kN/m3 c) 0.339 mm/s )
- The speed limit on some interstate highways is roughly 100 km/h. (a) What is this in meters per second? (b) How many miles per hour is this? (Answer (a) 27.8 m/s b) 62.1 miles per hour or mph)
- A car is traveling at a speed of 33 m/s. What is its speed in kilometres per hour? Is it exceeding the 90 km/h speed limit? (Answer 118.8 km/h so yes it is speeding)
- Show that 1.0 m/s=3.6 km/h. Hint: Show the explicit steps involved in converting 1.0 m/s=3.6 km/h. (Answer [latex]\frac{1.0 \: m } {s} = \frac {1.0 \: m }{s} \times \frac{ 3600 \: s}{1 \: { hr}} \times \frac{1\: { km}}{1000 \: { m}}[/latex] = 3.6 km/h. )
- American football is played on a 100-yd-long field, excluding the end zones. How long is the field in meters? Remember that 1 yard = 3 feet and 1 foot = 0.3048 m. (Answer 91.4 m).
- Soccer fields vary in size. A large soccer field is 115 m long and 85 m wide. What are its dimensions in feet and inches? Remember that 1 meter equals 3.281 feet. (Answer length: 377 ft; 4.53 x 1 = 3 in width = 280 ft ; 3.3 x 103 inches )
- What is the height in meters of a person who is 6 ft 1.0 in. tall? Remember that 1 meter equals 39.37 in. and there are 12 inches in one foot. (Answer: 1.85 m)
- Mount Everest, at 29,031.7 feet, is the tallest mountain on the Earth. Wh