From bicycle tires and jar lids to shovels and doorknobs, the world is full of objects that help people perform basic tasks more easily. Simple Machines examines the six most common mechanisms, with... This description may be from another edition of this product.
ThriftBooks sells millions of used books at the lowest everyday prices. We personally assess every book's quality and offer rare, out-of-print treasures. We deliver the joy of reading in recyclable packaging with free standard shipping on US orders over $15. ThriftBooks.com. Read more. Spend less.