July 9, Week 6 Today: Chapter 10, Elastic Potential Energy Homework - PowerPoint PPT Presentation

July 9, Week 6 Today: Chapter 10, Elastic Potential Energy Homework #6 due Friday Office hours today, 1:00-5:00 Elastic Energy 9th July 2014

Hooke’s Law A simple example of a variable force is the force needed to stretch a spring. Elastic Energy 9th July 2014

Hooke’s Law A simple example of a variable force is the force needed to stretch a spring. Elastic Energy 9th July 2014

Hooke’s Law A simple example of a variable force is the force needed to stretch a spring. Hooke’s Law - The force needed to stretch or compress a spring increases linearly with stretching distance Elastic Energy 9th July 2014

Hooke’s Law A simple example of a variable force is the force needed to stretch a spring. Hooke’s Law - The force needed to stretch or compress a spring increases linearly with stretching distance Elastic Energy 9th July 2014

Hooke’s Law A simple example of a variable force is the force needed to stretch a spring. Hooke’s Law - The force needed to stretch or compress a spring increases linearly with stretching distance Elastic Energy 9th July 2014

Hooke’s Law A simple example of a variable force is the force needed to stretch a spring. Hooke’s Law - The force needed to stretch or compress a spring increases linearly with stretching distance s Elastic Energy 9th July 2014

Hooke’s Law A simple example of a variable force is the force needed to stretch a spring. Hooke’s Law - The force needed to stretch or compress a spring increases linearly with stretching distance F sp = ks s Elastic Energy 9th July 2014

Hooke’s Law A simple example of a variable force is the force needed to stretch a spring. Hooke’s Law - The force needed to stretch or compress a spring increases linearly with stretching distance F sp = ks s k = spring constant, Unit: N/m s = stretching distance Elastic Energy 9th July 2014

Hooke’s Law A simple example of a variable force is the force needed to stretch a spring. Hooke’s Law - The force needed to stretch or compress a spring l o increases linearly with stretching distance F sp = ks s k = spring constant, Unit: N/m s = stretching distance Elastic Energy 9th July 2014

Hooke’s Law A simple example of a variable force is the force needed to stretch a spring. Hooke’s Law - The force needed to stretch or compress a spring l o increases linearly with stretching distance l F sp = ks s k = spring constant, Unit: N/m s = stretching distance Elastic Energy 9th July 2014

Hooke’s Law A simple example of a variable force is the force needed to stretch a spring. Hooke’s Law - The force needed to stretch or compress a spring l o increases linearly with stretching distance l F sp = ks s k = spring constant, Unit: N/m s = l − l o s = stretching distance Elastic Energy 9th July 2014

Spring Exercise F sp = ks A horizontal 50 - N force is applied to a 100 N/m spring whose unstretched length is 0 . 5 m . What is the spring’s length after the force has been applied? 50 N Elastic Energy 9th July 2014

Spring Exercise F sp = ks A horizontal 50 - N force is applied to a 100 N/m spring whose unstretched length is 0 . 5 m . What is the spring’s length after the force has been applied? (a) 0 m 50 N Elastic Energy 9th July 2014

Spring Exercise F sp = ks A horizontal 50 - N force is applied to a 100 N/m spring whose unstretched length is 0 . 5 m . What is the spring’s length after the force has been applied? (a) 0 m (b) 0 . 5 m 50 N Elastic Energy 9th July 2014

Spring Exercise F sp = ks A horizontal 50 - N force is applied to a 100 N/m spring whose unstretched length is 0 . 5 m . What is the spring’s length after the force has been applied? (a) 0 m (b) 0 . 5 m 50 N (c) 1 m Elastic Energy 9th July 2014

Spring Exercise F sp = ks A horizontal 50 - N force is applied to a 100 N/m spring whose unstretched length is 0 . 5 m . What is the spring’s length after the force has been applied? (a) 0 m (b) 0 . 5 m 50 N (c) 1 m (d) 1 . 5 m Elastic Energy 9th July 2014

Spring Exercise F sp = ks A horizontal 50 - N force is applied to a 100 N/m spring whose unstretched length is 0 . 5 m . What is the spring’s length after the force has been applied? (a) 0 m (b) 0 . 5 m 50 N (c) 1 m (d) 1 . 5 m (e) 2 m Elastic Energy 9th July 2014

Spring Exercise F sp = ks A horizontal 50 - N force is applied to a 100 N/m spring whose unstretched length is 0 . 5 m . What is the spring’s length after the force has been applied? (a) 0 m (b) 0 . 5 m (c) 1 m 50 N (d) 1 . 5 m (e) 2 m Elastic Energy 9th July 2014

Spring Exercise F sp = ks A horizontal 50 - N force is applied to a 100 N/m spring whose unstretched length is 0 . 5 m . What is the spring’s length after the force has been applied? l 0 = 0 . 5 m s = 0 . 5 m (c) 1 m 50 N l 50 N s = 100 N/m = 0 . 5 m Elastic Energy 9th July 2014

Spring Exercise II F sp = ks A 5 - kg mass is attached, as shown, to a 100 N/m spring whose unstretched length is 0 . 5 m . If the mass is pushed 0 . 3 m to the left, what is the magnitude and direction of the force exerted by the spring on the mass? 0 . 3 m Elastic Energy 9th July 2014

Spring Exercise II F sp = ks A 5 - kg mass is attached, as shown, to a 100 N/m spring whose unstretched length is 0 . 5 m . If the mass is pushed 0 . 3 m to the left, what is the magnitude and direction of the force exerted by the spring on the mass? (a) 30 N, Left 0 . 3 m Elastic Energy 9th July 2014

Spring Exercise II F sp = ks A 5 - kg mass is attached, as shown, to a 100 N/m spring whose unstretched length is 0 . 5 m . If the mass is pushed 0 . 3 m to the left, what is the magnitude and direction of the force exerted by the spring on the mass? (a) 30 N, Left (b) 30 N, Right 0 . 3 m Elastic Energy 9th July 2014

Spring Exercise II F sp = ks A 5 - kg mass is attached, as shown, to a 100 N/m spring whose unstretched length is 0 . 5 m . If the mass is pushed 0 . 3 m to the left, what is the magnitude and direction of the force exerted by the spring on the mass? (a) 30 N, Left (b) 30 N, Right 0 . 3 m (c) 20 N, Left Elastic Energy 9th July 2014

Spring Exercise II F sp = ks A 5 - kg mass is attached, as shown, to a 100 N/m spring whose unstretched length is 0 . 5 m . If the mass is pushed 0 . 3 m to the left, what is the magnitude and direction of the force exerted by the spring on the mass? (a) 30 N, Left (b) 30 N, Right 0 . 3 m (c) 20 N, Left (d) 20 N, Right Elastic Energy 9th July 2014

Spring Exercise II F sp = ks A 5 - kg mass is attached, as shown, to a 100 N/m spring whose unstretched length is 0 . 5 m . If the mass is pushed 0 . 3 m to the left, what is the magnitude and direction of the force exerted by the spring on the mass? (a) 30 N, Left (b) 30 N, Right 0 . 3 m (c) 20 N, Left (d) 20 N, Right (e) 50 N, Right Elastic Energy 9th July 2014

Spring Exercise II F sp = ks A 5 - kg mass is attached, as shown, to a 100 N/m spring whose unstretched length is 0 . 5 m . If the mass is pushed 0 . 3 m to the left, what is the magnitude and direction of the force exerted by the spring on the mass? (a) 30 N, Left (b) 30 N, Right 0 . 3 m (c) 20 N, Left (d) 20 N, Right (e) 50 N, Right Elastic Energy 9th July 2014

Spring Exercise II F sp = ks A 5 - kg mass is attached, as shown, to a 100 N/m spring whose unstretched length is 0 . 5 m . If the mass is pushed 0 . 3 m to the left, what is the magnitude and direction of the force exerted by the spring on the mass? F sp = (100 N/m ) (0 . 3 m ) (b) 30 N, Right s = 0 . 3 m Springs pull when stretched and push when compressed Elastic Energy 9th July 2014

Work to Stretch a Spring Elastic Energy 9th July 2014

Work to Stretch a Spring s i Elastic Energy 9th July 2014

Work to Stretch a Spring s i Elastic Energy 9th July 2014

Work to Stretch a Spring s i s f Elastic Energy 9th July 2014

Work to Stretch a Spring F s s i s f Elastic Energy 9th July 2014

Work to Stretch a Spring F F sp = ks s s i s f Elastic Energy 9th July 2014

Work to Stretch a Spring F F sp = ks s s i s f Elastic Energy 9th July 2014

Work to Stretch a Spring F F sp = ks s s i s f s i s f Elastic Energy 9th July 2014

Work to Stretch a Spring F F sp = ks s s i s f s i s f Elastic Energy 9th July 2014

Work to Stretch a Spring F F sp = ks F f F i s s i s f s i s f W = 1 2 ( s f )( F f ) − 1 2 ( s i )( F i ) Elastic Energy 9th July 2014

Work to Stretch a Spring F F sp = ks F f F i s s i s f s i s f W = 1 2 ( s f )( F f ) − 1 2 ( s i )( F i ) W = 1 2 ( s f )( ks f ) − 1 2 ( s i )( ks i ) Elastic Energy 9th July 2014

Work to Stretch a Spring F F sp = ks F f F i s s i s f s i s f W = 1 2 ( s f )( F f ) − 1 2 ( s i )( F i ) W = 1 2 ( s f )( ks f ) − 1 2 ( s i )( ks i ) W = 1 f − 1 2 ks 2 2 ks 2 i Elastic Energy 9th July 2014

Elastic Potential Energy Elastic Potential energy - Potential energy due to a spring. Elastic Energy 9th July 2014

Elastic Potential Energy Elastic Potential energy - Potential energy due to a spring. Elastic Energy 9th July 2014

Elastic Potential Energy Elastic Potential energy - Potential energy due to a spring. 0 Elastic Energy 9th July 2014