Multiple-Concept Example 10 reviews the approach and some of the concepts that are pertinent to this problem. The figure shows a model for the motion of the human forearm in throwing a dart. Because of the force M→ applied by the triceps muscle, the forearm can rotate about an axis at the elbow joint. Assume that the forearm has the dimensions shown in the figure and a moment of inertia of 0.067 kg·m2 (including the effect of the dart) relative to the axis at the elbow. Assume also that the force M→ acts perpendicular to the forearm. Ignoring the effect of gravity and any frictional forces, determine the magnitude of the force M→ needed to give the dart a tangential speed of 6.7 m/s in 0.14 s, starting from rest. A flywheel is a solid disk that rotates about an axis that is perpendicular to the disk at its center. Rotating flywheels provide a means for storing energy in the form of rotational kinetic energy and are being considered as a possible alternative to batteries in electric cars. The gasoline burned in a 144-mile trip in a typical midsize car produces about 1.05 x 109 J of energy. How fast would a 18.7-kg flywheel with a radius of 0.247 m have to rotate to store this much energy? Give your answer in rev/min. Number Type your answer here Units Choose your answer here
Multiple-Concept Example 10 reviews the approach and some of the concepts that are pertinent to this problem. The figure shows a model for the motion of the human forearm in throwing a dart. Because of the force M→ applied by the triceps muscle, the forearm can rotate about an axis at the elbow joint. Assume that the forearm has the dimensions shown in the figure and a moment of inertia of 0.067 kg·m2 (including the effect of the dart) relative to the axis at the elbow. Assume also that the force M→ acts perpendicular to the forearm. Ignoring the effect of gravity and any frictional forces, determine the magnitude of the force M→ needed to give the dart a tangential speed of 6.7 m/s in 0.14 s, starting from rest.
A flywheel is a solid disk that rotates about an axis that is perpendicular to the disk at its center. Rotating flywheels provide a means for storing energy in the form of rotational kinetic energy and are being considered as a possible alternative to batteries in electric cars. The gasoline burned in a 144-mile trip in a typical midsize car produces about 1.05 x 109 J of energy. How fast would a 18.7-kg flywheel with a radius of 0.247 m have to rotate to store this much energy? Give your answer in rev/min.
| Number | Type your answer here | Units | Choose your answer here |
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