# Technical Measurement and Vector

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Chapter 1: Technical Measurement and Vector 5. Newton’s law of universal gravitation is represented by [pic] where F is the gravitational force, M and m are masses, and r is a length. Force has the SI units kg ∙ m/s2. What are the SI units of the proportionality constant G? 8. The speed of light is now defined to be 2.99 7924 58 × 108 m/s. Express the speed of light to (a) three significant figures, (b) five significant figures, and (c) seven significant figures. 15. A rectangular building lot measures 100 ft by 150 ft. Determine the area of this lot in square meters (m2). 19. The speed of light is about 3.00 × 108 m/s. Convert this figure to miles per hour. 22. (a) Find a conversion factor to convert from miles per…show more content…
A 500-N uniform rectangular sign 4.00 m wide and 3.00 m high is suspended from a horizontal, 6.00-m-long, uniform, 100-N rod as indicated in Figure P8.17. The left end of the rod is supported by a hinge, and the right end is supported by a thin cable making a 30.0° angle with the vertical. (a) Find the tension T in the cable. (b) Find the horizontal and vertical components of force exerted on the left end of the rod by the hinge. [pic] 20. A 20.0-kg floodlight in a park is supported at the end of a horizontal beam of negligible mass that is hinged to a pole, as shown in Figure P8.20. A cable at an angle of 30.0° with the beam helps to support the light. Find (a) the tension in the cable and (b) the horizontal and vertical forces exerted on the beam by the pole. [pic] 21. A uniform plank of length 2.00 m and mass 30.0 kg is supported by three ropes, as indicated by the blue vectors in Figure P8.21. Find the tension in each rope when a 700-N person is 0.500 m from the left end. [pic] 26. One end of a uniform 4.0-m-long rod of weight w is supported by a cable. The other end rests against a wall, where it is held by friction. (See Fig. P8.26.) The coefficient of static friction between the wall and the rod is μs = 0.50. Determine the minimum distance x from point A at which an additional weight w (the same as the weight of the rod) can be hung without causing the rod to slip at point A. [pic] Chapter 4: