The highest point of a wave is the crest. The lowest point is the trough. The vertical distance between a crest and a trough is the height of the wave. Wave height is also called amplitude. The horizontal distance between two crests is the wavelength. Both amplitude and wavelength are measures of wave size. The size of an ocean wave depends on how fast, over how great a distance, and how long the wind blows. The greater each of these factors is, the bigger a wave will be. Some of the biggest waves occur with hurricanes. A hurricane is a storm that forms over the ocean. Its winds may blow more than 150 miles per hour! The winds also travel over long distances and may last for many days. 

Question: "When concerning wave height, what are the highest and lowest points called?"

Response: "The crest and trough"

A: yes


What if two children push a swing at the same time? Would the swing go higher? Yes, together their force would be more. It is common for forces to be combined. Most objects on Earth have at least two forces acting on them. Do you know what one of them is? Of course, that force is gravity. How many forces do you have on you right now? Gravity pulls you down toward the center of Earth. Your legs exert a downward force. They hold you up against the pull of gravity. Consider the example in Figure 1.3. A book is resting on a table. Gravity pulls the book downward. It has a force of 20 newtons. At the same time, the table pushes the book upward. Its force is also 20 newtons. The table opposes the pull of gravity. 

Question: "Give two examples of combined forces action on an object"

Response: "Forces cannot combine together to act on an object"

A: no


For much of the world, the Algarve is synonymous with Portugal, yet the Portuguese will tell you the exact opposite: the region has little in common with the rest of the country. The southern stretch of coast is more reminiscent of a North African landscape than a European one. It has no cosmopolitan cities, like Lisbon and Porto, which are farther north. Most of Portugal is known for quaint towns, medieval castles, and grand palaces. The Algarve is more recognizable for impenetrable blocks of tourist apartments, hotels, and meticulously manicured golf courses. And beaches. Think Algarve and the mind pictures long, glorious stretches of golden sands, secluded coves framed by odd ochre-colored rock formations, and deep green waters. With about 160 km (100 miles) of coastline, Portugal's southern province is one of Europe's premier beach destinations. The occasionally chilly ocean is the Atlantic, but the Algarve has a sultry Mediterranean feel. Its consistent climate is the best in Portugal, and one of the kindest in the world: more than 250 days of sunshine a year — more than almost any other international resort area. The moderating effect of the Gulf Stream produces a fresh springtime breeze throughout winter, and in late January and February, white almond blossoms blanket the fields. In summer the heat is intense but rarely unbearable, and regardless, beautiful beaches and innumerable pools are always just a dive away. Magnificent year-round weather has made the Algarve a huge destination for sporting vacations. Superb golf facilities abound — several with tees dramatically clinging to cliffs and fairways just skirting the edge of the ocean — and horseback riding, tennis, big-game fishing, sailing, and windsurfing are immensely popular. Sports, beaches and hospitable weather — not to mention easily organized package vacations — are surely the reasons the Algarve receives as many visitors as the rest of Portugal in its entirety. But it's not just international tourists that descend on the Algarve; many Portuguese from Lisbon and elsewhere in the north have holiday homes and spend their summer vacations here. The coast is neatly divided into the rugged Barlavento to the west and the flat beauty of Sotavento to the east. West is where you'll find the famous orange cliffs and surreal eroded rock stacks. 

Question: "Is the Algarve known for quaint towns, medieval castles, and grand palaces?"

Response: "No, the Algarve region is mostly known for the many luxurious tourist apartments, hotels, golf courses, and beaches"

A:
yes