Answer to Question #247593 in Mechanics | Relativity for Jack

Question

Two identical spheres of known mass M are attached to opposite ends of a rod of negligible mass. The mass-rod-mass system is spun in the vertical plane and then released so the system falls downward as it rotates, as shown in the figure. Data are collected and shown in the graph of the vertical velocity, v, of the two spheres as a function of time .The positive direction is considered to be downward. A student uses the graph to make three claims. Claim 1: Change in linear momentum of the center of mass of the system from 0.0s to 0.5s can be determined. Claim 2 The average applied force exerted on the center of mass of the system from 0.0s to 0.5s can be determined.Claim 3: The change in the kinetic energy of the system from 0.0s to 0.5s can be determined. Which of the student's claims are correct

Answer A: Claim 1 and claim 2 only

Answer B: Claim 1 and claim 3 only

Answer C: Claim 2 and claim 3 only

D:Claim 1, claim 2, and claim 3

Answer 1

Answer : option d

The centre of mass of the object will not have any horizontal displacement. So as a whole ,the system will undergo a vertical motion starting from rest and acceleration will be equal to acceleration due gravity ( g= 9.8m/s^2)

So change in linear momentum of center of mas, force on the centre of mass and change in kinetic energy of the system can be determined.