Question: 1 give answers to the follwing questions. 1) If two particles have equ

Question

Question: 1 give answers to the follwing questions.

1)      If two particles have equalkinetic energies, are their momenta necessarily equal?Explain.                                                                                                                                                       

2)Where is the center of mass of Earth's atmosphere?                                             

3)An airplane propeller is rotating at 1900 rev/min.Compute thepropeller's angular velocity inrad/s.                                                                                                                   

4)Two ice dancers are at rest on the ice, facing each other withtheir hands together. They push off on each other in order to seteach other in motion. The subsequent momentum change (magnitudeonly) of the two skaters will be ____. Also write it’s (theanswer you choose) detail reason

A. greatest for the skater who is pushed upon with the greatestforce

B. greatest for the skater who pushes with the greatestforce

C. the same for each skater

D. greatest for the skater with the most mass

E. greatest for the skater with the leastmass                

5)How much work is done by an applied force to lift a 20-Newtonblock 2.0 meters vertically at a constantspeed?                                                                                

A student with a mass of 50.0 kg runs up three flights of stairsin 10.0 sec. The student has gone a vertical distance of 8.0 m.Determine the amount of work done by the student to elevate hisbody to this height. Assume that her speed is constant

Explanation / Answer

Q#1>>>   IF IF the two particles have thesame mass, then they would have the same momenta. However,the question does not specify the masses, so we cannot make theassumption that the masses are equal.   For differentmasses with the same KE, the momenta will be different.  The eqn that related KE and momentum p is   KE =p2 / 2m.    Or, p = 2 m KE.   Thus, different masses willhave different momenta, for constant KE. Q#2>>> CM for atmosphere is at geometricalcenter of the earth, since that is the point of symmetry of thespherical layer of air. Q#3>>> ( 1900 rev/min ) ( 2 rad /rev) ( 1 min / 60 sec ) = 63.33 rad/sec or 199 rad/sec. Q#4>>>>    C. same for eachskater.    Total momentum before pushing off iszero, so the law of conservation of momentum says that the totalmomentum after the pushoff will also be zero. Thatmeans that each skater must have exactly the same momentum, but inopposite directions, so the two momentum vectors cancel out to givea result of zero. Q#5>>>> work = (mg) h = (20N) (2m) = 40 Joules          work = m g h   = (50kg) (9.8 m/s2 ) (8m ) = 3920 Joules.

Related Questions

Navigate

• Browse (All)
• Browse Q
• Subjects

---

---

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