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10. -2 points SerCP10 6.P.022. My Notos Ask Your Teacher A rifle with a weight o

ID: 1864369 • Letter: 1

Question

10. -2 points SerCP10 6.P.022. My Notos Ask Your Teacher A rifle with a weight of 25 N fires a 4.5-g bullet with a speed of 290 m/s. (a) Find the recoil speed of the rifle. m/s (b) If a 625-N man holds the rifle firmly against his shoulder, find the recoil speed of the man and rifle. m/s Need Help?Read in 11. -/2 points SerCP10 6.P.023 My Notes Ask Your Teache A 45.0-kg girl is standing on a 160-kg plank. The plank, originally at rest, is free to slide on a frozen lake, which is a flat, frictionless surface. The girl begins to walk along the plank at a constant velocity of 1.31 m/s to the right relative to the plank. (Let the direction the girl is moving in be positive. Indicate the direction with the sign of your answer.) (a) What is her velocity relative to the surface of ice? m/s (b) What is the velocity of the plank relative to the surface of ice? m/s Need Help?Read it

Explanation / Answer

10) BY the conservation of momentum we have

m1u1 = m2u2

(0.0045*290) = (25 / 9.8) *(u2)

u2 = 0.51 m/s

b) m1u1 = m2u2

0.0045*290 = (625 + 25 / 9.8) *u2

u2 = 0.02 m/s