You and your friends are doing physics experiments on a frozen pond that serves

Question

You and your friends are doing physics experiments on a frozen pond that serves as a frictionless, horizontal surface. Sam, with mass 80.0 kg. is given a push and slides eastward. Abigail, with mass 50.0 kg, is sent sliding northward. They collide, and after the collision Sam is moving at 37.0 degree north of east with a speed of 6.00 m/s and Abigail is moving at 23.0 degree south of cast with a speed of 9.00 m/s. What was the speed of each person before the collision By how much did the total kinetic energy of the two people decrease dourine the collision

Explanation / Answer

m1(sam) = 80 kg              m2(Abigail) = 50 kg

before collision

speeds

u1x = ?                       u2x = 0

u1y = 0                          u2y = ?

after collision

v1x = 6*cos37                       v2x = 9*cos23

v1y = 6*sin37 m/s                   v2y = -9*sin23

from momentum conservation

along x axis

Pix = Pfx

m1*u1x + m2*u2x = m1*v1x + m2*v2x

80*u1x + 0 = (80*6*cos37)+ (50*9*cos23)

u1x (sam)= 9.97 m/s <<-------answer

along y

Piy = Pfy

m1*u1y + m2*u2y = m1*v1y + m2*v2y

0 + 50*u2y = (80*6*sin37)-(50*9*sin23)

u2y (Abigail) = 2.26 m/s <<------answer

+++++++++

b)

KEi = 0.5*m1*u1x^2 + 0.5*m2*u2y^2

KEi = (0.5*80*9.97^2)+(0.5*50*2.26^2) = 4103.726 J

KEf = 0.5*m1*v1^2 + 0.5*m2*v2^2

KEf = (0.5*80*6^2)+(0.5*50*9^2) = 3465 J

decrease = 4103.726-3465 = 638.726 J

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.