{"id":705,"date":"2020-06-06T22:04:24","date_gmt":"2020-06-06T22:04:24","guid":{"rendered":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/?p=705"},"modified":"2021-03-09T01:26:18","modified_gmt":"2021-03-09T01:26:18","slug":"section-12-2","status":"publish","type":"post","link":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/2020\/06\/06\/section-12-2\/","title":{"rendered":"Chapter 12: Kinematics"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">12.2 Projectile motion<\/h2>\n\n\n\n<p>A projectile is any object that is thrown or launched. As with 1D kinematics problems, we\u2019re not concerned with what caused the object to be launched, or how it was launched in the first place. All we care about is what happens <em>after<\/em> it has been launched. At that point, the only force acting on the object is gravity, when air resistance can be neglected.<\/p>\n\n\n\n<p>Now, consider two identical projectiles: one dropped from rest and the other thrown horizontally from the same height, at the same time.<\/p>\n\n\n\n<p>Newton\u2019s first law (<a href=\"https:\/\/books.compclassnotes.com\/rothphys110-2e\/2020\/04\/08\/section-9-2\/\" target=\"_blank\" rel=\"noreferrer noopener\">section 9.2<\/a>) tells us that an object\u2019s velocity only changes if there is some force applied to it. For both of the objects, the only force exerted is gravity, which only acts in the vertical direction. Therefore, only the <em>vertical<\/em> component of a projectile\u2019s velocity changes. The acceleration in the vertical direction is <em>g<\/em>. There is zero acceleration in the horizontal direction. (Of course, these statements are only true as long as air resistance can be neglected.)<\/p>\n\n\n\n<p>Returning to our two objects, we note that the vertical component of each object\u2019s velocity is zero, the rate of change of each object\u2019s velocity is the same, and they fall the same vertical distance\u2014in the vertical direction everything is identical!<\/p>\n\n\n\n<p>The vertical and horizontal components of motion are independent from one another. Solving two-dimensional problems is the same as solving one-dimensional problems, except that there is more information to work with. This is where proper organization becomes very important for helping you solve the problem efficiently.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Example<\/h4>\n\n\n\n<!-- iframe plugin v.6.0 wordpress.org\/plugins\/iframe\/ -->\n<iframe loading=\"lazy\" src=\"https:\/\/my.compclassnotes.com\/canonical\/PHYS110\/PHYS110_book_ch12_2_EXMPL\" width=\"100%\" height=\"800\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"yes\" class=\"iframe-class\" frameborder=\"0\"><\/iframe>\n\n\n\n\n<h4 class=\"wp-block-heading\">Practice<\/h4>\n\n\n\n<!-- iframe plugin v.6.0 wordpress.org\/plugins\/iframe\/ -->\n<iframe loading=\"lazy\" src=\"https:\/\/my.compclassnotes.com\/canonical\/PHYS110\/kinematics_constant_acceleration_AI_prac_2d\" width=\"100%\" height=\"800\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"yes\" class=\"iframe-class\" frameborder=\"0\"><\/iframe>\n\n","protected":false},"excerpt":{"rendered":"<p>12.2 Projectile motion A projectile is any object that is thrown or launched. As with 1D kinematics problems, we\u2019re not concerned with what caused the object to be launched, or how it was launched in the first place. All we <span class=\"readmore\"><a href=\"https:\/\/books.compclassnotes.com\/rothphys110-2e\/2020\/06\/06\/section-12-2\/\">Continue Reading<\/a><\/span><\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-705","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/posts\/705","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/comments?post=705"}],"version-history":[{"count":2,"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/posts\/705\/revisions"}],"predecessor-version":[{"id":808,"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/posts\/705\/revisions\/808"}],"wp:attachment":[{"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/media?parent=705"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/categories?post=705"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/books.compclassnotes.com\/rothphys110-2e\/wp-json\/wp\/v2\/tags?post=705"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}