🎉 Announcing Numerade's $26M Series A, led by IDG Capital!Read how Numerade will revolutionize STEM Learning Numerade Educator ### Problem 40 Easy Difficulty # You and your friends are doing physics experiments on a frozen pond that serves as a frictionless, horizontal surface. Sam, with mass 80.0$\mathrm{kg}$, is given a push and slides eastward. Abigail, with mass 50.0$\mathrm{kg}$, is sent sliding northward. They collide, and after the collision Sam is moving at$37.0^{\circ}$north of east with a speed of 6.00$\mathrm{m} / \mathrm{s}$and Abigail is moving ar$23.0^{\circ}$south of east with a speed of 9.00$\mathrm{m} / \mathrm{s}$. (a) What was the speed of each person before the collision? (b) By how much did the total kinetic energonof the two people decrease during the collision? ### Answer ## (a)$2.26 \mathrm{m} / \mathrm{s}$(b)$-639 \mathbf{J}\$

#### Topics

Moment, Impulse, and Collisions

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##### Christina K.

Rutgers, The State University of New Jersey

##### Farnaz M.

Simon Fraser University

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### Video Transcript

um, given and when the most off them ISS 80 k g and and to myself, I'll be a big girl and just a kitchen Did you want And uh huh we want we have to find on speed. You are too is zero. But this is you on x. This is you two x, um and you want Why is zero? And if you do, why is toe be found after collision? Do you want X is six cause 35 um to X is nine course 20 three and villain white is six. Sign 37 the two Why is minus 99 23 from Mo Mentum Conversation Cancer from a momentum conservation along X axis E x is a girl toe fx therefore And when you want X plus m to you two x is equal to and one B one eggs us and 232 Next, this is a day multiplied by U. N. X zero is a girl toe 50 into six into six cost 37 plus 50 into nine cost 20 She well you want thank That is sound is a call to 9.97 m per second I thought along. Why the i've I Is it going to be asked to white that is equal to And one you want a but and to you too. X is equal toe and one b one x for us and to Beto. Okay, that is a day multiplied. Five. You want X? Yes, there is a going toe a day multiplied by six cost 37 plus 52 9 course 20. See therefore but sign 37 this 9 27 9 23. So you Yeah. So this is why. Why? Why? What? No you want? Why history. You too, you toe Why, That is a big girl or toe point to save meter 1st. 2nd? Yeah, second kind of tick energy is a contra 0.5 and two and one and two. You want excellence Do. Plus a little 0.5 and two u two way to the bar. I'm a square. So so their 0.5 into Ambon is 80 into 9.97 square that 0.5 in tow. 50 into 2.26 where there is a 400 4103.726 jewels and frantic energy. Final is 0.5 and one. The one square plus 0.5 and two. What do you do? Good. That this little 0.5 and one is 50 and to be 16 square. That 0.5 and two this day into nine didn't square good it 34652 Therefore decrease. They could do 4103.7 to 6 minus 3465 Jews, that is 6 38. Find 7 to 6 Jews.

#### Topics

Moment, Impulse, and Collisions

##### Christina K.

Rutgers, The State University of New Jersey

##### Farnaz M.

Simon Fraser University

Lectures

Join Bootcamp