A bullet with a mass of 80 g is shot by a rifle and has a speed of 250 m/s. If t

Question

A bullet with a mass of 80 g is shot by a rifle and has a speed of 250 m/s. If the recoil speed of the rifle is 5 m/s. what is the mass of the rifle as the bullet is fired? During the 2014 Winter Olympics Women's 3000 m short track speed-skating relay race, Shim Suk-Hee pushes her teammate from behind to give her a boost as they relay the race. Just before the push Shim is skating at a speed of 9.0 m/s and her teammate, Park Seung-Hi, is skating at a speed of 4 m/s. After the push Shim slows down to 2.5 m/s. If Shim has a mass of 58 kg, and Park has a mass of 54 kg, what is Park's speed after she is pushed?

Explanation / Answer

3)

let the mass of rifle is m

Using conservation of momentum

magnitude of momentum of bullet after firing = magnitude of momentum of rifle after firing

80 * 250 = m* 5

m = 4000 gm = 4 Kg

the mass of rifle is 4 Kg

4)

let the Park's speed after the push is vf

Using conservation of momentum

momentum of system before push = momentum of system after the push

58 * 9 + 54 * 4 = 58 * 2.5 + 54 * vf

vf = 11 m/s

the final speed of Park after the push is 11 m/s

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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