Modified Mastering Physics with Pearson eText -- Combo Access -- for Physics for Scientist and Engineers (18 week)
5th Edition
ISBN: 9780137504299
Author: Douglas C. Giancoli
Publisher: Pearson Education (US)
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Chapter 12, Problem 12Q
To determine
The reason why it is more difficult to do sit-ups when the knees are bent than when the legs are stretched out.
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Chapter 12 Solutions
Modified Mastering Physics with Pearson eText -- Combo Access -- for Physics for Scientist and Engineers (18 week)
Ch. 12.1 - Prob. 1AECh. 12.2 - We did not need to use the force equation to solve...Ch. 12.2 - CHAPTER-OPENING QUESTIONGuess Now! The diving...Ch. 12.2 - Why is it reasonable to ignore friction along the...Ch. 12.3 - Prob. 1EECh. 12.5 - Two steel wires have the same length and are under...Ch. 12 - Describe several situations in which an object is...Ch. 12 - A bungee jumper momentarily comes to rest at the...Ch. 12 - Prob. 3QCh. 12 - Your doctors scale has arms on which weights slide...
Ch. 12 - A ground retaining wall is shown in Fig. 1240a....Ch. 12 - Can the sum of the torques on an object be zero...Ch. 12 - A ladder, leaning against a wall, makes a 60 angle...Ch. 12 - Prob. 8QCh. 12 - Prob. 9QCh. 12 - Place yourself facing the edge of an open door....Ch. 12 - Prob. 11QCh. 12 - Prob. 12QCh. 12 - Prob. 13QCh. 12 - Which of the configurations of brick, (a) or (b)...Ch. 12 - Is the Youngs modulus for a bungee cord smaller or...Ch. 12 - Examine how a pair of scissors or shears cuts...Ch. 12 - Materials such as ordinary concrete and stone are...Ch. 12 - Prob. 1MCQCh. 12 - Prob. 2MCQCh. 12 - Prob. 3MCQCh. 12 - Prob. 4MCQCh. 12 - Prob. 5MCQCh. 12 - Prob. 6MCQCh. 12 - Prob. 7MCQCh. 12 - Prob. 8MCQCh. 12 - Prob. 9MCQCh. 12 - Prob. 10MCQCh. 12 - Prob. 11MCQCh. 12 - (I) A tower crane (Fig. 1248a) must always be...Ch. 12 - Prob. 2PCh. 12 - Prob. 3PCh. 12 - Prob. 4PCh. 12 - (II) Calculate the forces FA and FB that the...Ch. 12 - Prob. 6PCh. 12 - Prob. 7PCh. 12 - Prob. 8PCh. 12 - Prob. 9PCh. 12 - (II) Find the tension in the two wires supporting...Ch. 12 - Prob. 12PCh. 12 - (II) The force required to pull the cork out of...Ch. 12 - Prob. 14PCh. 12 - (II) Three children are trying to balance on a...Ch. 12 - Prob. 16PCh. 12 - (II) A traffic light hangs from a pole as shown in...Ch. 12 - Prob. 18PCh. 12 - Prob. 19PCh. 12 - Prob. 20PCh. 12 - Prob. 21PCh. 12 - Prob. 22PCh. 12 - Prob. 23PCh. 12 - (III) A door 2.30 m high and 1.30 m wide has a...Ch. 12 - Prob. 25PCh. 12 - Prob. 26PCh. 12 - Prob. 27PCh. 12 - (III) A uniform ladder of mass m and length leans...Ch. 12 - (III) A refrigerator is approximately a uniform...Ch. 12 - (III) A 56.0-kg person stands 2.0 m from the...Ch. 12 - Prob. 31PCh. 12 - Prob. 33PCh. 12 - Prob. 34PCh. 12 - Prob. 35PCh. 12 - Prob. 36PCh. 12 - Prob. 37PCh. 12 - Prob. 38PCh. 12 - Prob. 39PCh. 12 - Prob. 40PCh. 12 - (I) A sign (mass 1700 kg) hangs from the end of a...Ch. 12 - Prob. 42PCh. 12 - (II) How much pressure is needed to compress the...Ch. 12 - (II) At depths of 2000 m in the sea, the pressure...Ch. 12 - Prob. 45PCh. 12 - (I) The femur bone in the human leg has a minimum...Ch. 12 - Prob. 47PCh. 12 - (II) (a) What is the maximum tension possible in a...Ch. 12 - (II) If a compressive force of 3.3 104 N is...Ch. 12 - Prob. 50PCh. 12 - (II) Assume the supports of the uniform cantilever...Ch. 12 - Prob. 52PCh. 12 - Prob. 53PCh. 12 - Prob. 54PCh. 12 - Prob. 55PCh. 12 - (III) The truss shown in Fig. 1272 supports a...Ch. 12 - (II) How high must a pointed arch be if it is to...Ch. 12 - Prob. 60GPCh. 12 - A cube of side l rests on a rough floor. It is...Ch. 12 - Prob. 62GPCh. 12 - When a wood shelf of mass 6.6 kg is fastened...Ch. 12 - Prob. 64GPCh. 12 - Prob. 67GPCh. 12 - The mobile in Fig. 1274 is in equilibrium. Object...Ch. 12 - A 65.0-kg painter is on a uniform 25-kg scaffold...Ch. 12 - Prob. 70GPCh. 12 - Prob. 73GPCh. 12 - Prob. 74GPCh. 12 - Prob. 76GPCh. 12 - Prob. 77GPCh. 12 - Prob. 78GPCh. 12 - Prob. 79GPCh. 12 - Parachutists whose chutes have failed to open have...Ch. 12 - Prob. 81GPCh. 12 - One rod of the square frame shown in Fig. 1295...Ch. 12 - A uniform beam of mass M and length l is mounted...Ch. 12 - Prob. 84GPCh. 12 - A uniform 6.0-m-long ladder of mass 16.0 kg leans...Ch. 12 - In Fig. 1279, consider the right-hand...Ch. 12 - Assume that a single-span suspension bridge such...Ch. 12 - A uniform sphere of weight mg and radius r0 is...Ch. 12 - A uniform ladder of mass m and length leans at an...Ch. 12 - Prob. 90GPCh. 12 - Prob. 91GPCh. 12 - A 23-kg sphere rests between two smooth planes as...Ch. 12 - Prob. 93GPCh. 12 - Prob. 94GPCh. 12 - Prob. 95GP
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- When you carry a heavy load with one arm, why do you tend to hold your free arm away from your body?arrow_forwardA 75-kg man stands on his toes by exerting an upward force through the Achilles tendon, as shown. What is the force in the Achilles tendon if he stands on one foot?arrow_forwardWhen throwing a football you are always instructed to follow-through. What is the advantage of this? You are also instructed to stand with your feet about shoulder-width apart. What is the advantage of this?arrow_forward
- Why must you bend forward while carrying a heavy load on your back?arrow_forwardWhy Does A Cyclist Lean To One Side, While Going Along A Curve? In What Direction Does He Lean?arrow_forwardAssuming your feet are not held down, which is more difficult: doing sit-ups with your knees bent or with your legs straight out?arrow_forward
- A woman wearing a stiletto heel shoes (heel pointed shoes) gets tired and will feel pain in her legs easily. Why so?arrow_forwardDuring a circus act, one performer swings upside down hanging from a trapeze while holding another performer, also upside-down, by the calves. The legs (femurs) of the lower performer undergo deformation due to the upward force from the upper performer. If the upward force on the lower performer's legs is 3mg (three times her weight), how much do the bones (the femurs) in her upper legs stretch in meters? You may assume each bone is equivalent to a uniform rod 34 cm long and 1.75 cm in radius and the legs are massless, serving only to transmit the upward force on the torso. Her mass is 62 kg and Young's modulus for tension on bones is 1.6 × 1010 N/m2. ΔL =arrow_forwardThere is a small but appreciable amount of elastic hysteresis in the large tendon at the back of a horse’s leg. Explain how this can cause damage to the tendon if a horse runs too hard for too long a time.arrow_forward
- Why is it important to secure file cabinets to the floor, especially cabinets with heavy loads in top drawers?arrow_forwardA fireman at the scene of a fire is holding a heavy hose out of which water is gushing. To keep hisbalance, he often has to lean. Which way does he lean, forward or backward, and why?arrow_forwardWhen you bend your knee, the quadriceps muscle is stretched. This increases the tension in the quadriceps tendon attached to your kneecap (patella), which, in turn, increases the tension in the patella tendon that attaches your kneecap to your lower leg bone (tibia). Simultaneously, the end of your upper leg bone (femur) pushes outward on the patella. Shown is how these parts of a knee joint are arranged. What size force does the femur exert on the kneecap if the tendons are oriented as in the figure and the tension in each tendon is 60 N?arrow_forward
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