2. A particle starts from rest at time t = 0 and moves along the x axis. If the net force on it is proportional to t, its kinetic energy is proportional to: (A)\( t \) (B)\( t^2 \) (C)\( t^4 \) (D)\( 1/t^2 \) (E)\( 1/t \)

6. A uniform disk, a thin hoop, and a uniform sphere, all with the same mass and same outer radius, are each free to rotate about a fixed axis through its center. Assume the hoop is connected to the rotation axis by light spokes. With the objects starting from rest, identical forces are simultaneously applied to the rims, as shown. Rank the objects according to their angular momenta after a given time t, least to greatest. (A)all tie (B)disk, hoop, sphere (C)sphere, disk, hoop (D)hoop, sphere, disk (E)hoop, disk, sphere

2. A particle starts from rest at time t = 0 and moves along the x axis. If the net force on it is proportional to t, its kinetic energy is proportional to:

(A)\( t \)

(B)\( t^2 \)

(C)\( t^4 \)

(D)\( 1/t^2 \)

(E)\( 1/t \)

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