One of your classmates drew a force diagram for a pendulum bob at the bottom of its swing. He put a horizontal force arrow in the direction of the velocity. Evaluate his diagram by choosing from the statements below.<\/p>\n\n\n\n
(a) He is incorrect since the force should point partly forward and tilt partly down.<\/p>\n\n\n\n
(b) He is incorrect since there are no forces in the direction of the object\u2019s velocity.<\/p>\n\n\n\n
(c) He is correct since any moving object has a force in the direction of its velocity.<\/p>\n\n\n\n
(d) He is correct but he also needs to add an outward (down) force.<\/p>\n\n\n\n
The correct answer and explanation is :<\/strong><\/mark><\/p>\n\n\n\n Correct Answer: (b) He is incorrect since there are no forces in the direction of the object\u2019s velocity.<\/strong><\/p>\n\n\n\n In physics, a force diagram<\/strong> (also called a free-body diagram) is used to represent the forces acting on an object<\/strong>, not the direction of its motion or velocity. In the case of a pendulum bob at the bottom of its swing<\/strong>, it is crucial to distinguish between the direction of motion<\/strong> and the direction of forces<\/strong> acting on the object.<\/p>\n\n\n\n At the bottom of the swing<\/strong>, the pendulum bob is moving horizontally<\/strong> at its maximum speed<\/strong>. However, this motion does not imply<\/strong> that there is a force in the direction of the velocity. Newton\u2019s First Law tells us that an object in motion remains in motion unless acted on by a net external force<\/strong>. That means if the object is already moving, it does not need a force to keep it moving at that instant.<\/p>\n\n\n\n Instead, let\u2019s consider the actual forces<\/strong> acting on the pendulum bob at the bottom of its swing:<\/p>\n\n\n\n The net force<\/strong> on the bob at the bottom of the swing is actually directed upward<\/strong>, providing the centripetal force<\/strong> necessary to keep the pendulum moving in a circular path. This tension force is greater than the weight<\/strong> at this point, which creates a net upward force<\/strong>. Importantly, there is no net force in the direction of the bob\u2019s velocity<\/strong>, which is horizontal.<\/p>\n\n\n\n Therefore, placing a horizontal force arrow in the direction of velocity is incorrect because it confuses motion with force<\/strong>. Forces cause changes in motion<\/strong> (acceleration), not motion itself.<\/p>\n\n\n\n Thus, the correct evaluation is (b)<\/strong>.<\/p>\n","protected":false},"excerpt":{"rendered":" One of your classmates drew a force diagram for a pendulum bob at the bottom of its swing. He put a horizontal force arrow in the direction of the velocity. Evaluate his diagram by choosing from the statements below. (a) He is incorrect since the force should point partly forward and tilt partly down. (b) […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-211551","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/211551","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=211551"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/211551\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=211551"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=211551"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=211551"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n\n\n\nExplanation:<\/strong><\/h3>\n\n\n\n
\n