1. A block of mass m is initially moving to the right on a horizontal frictionless surface at a speed v. It then compresses a spring of spring constant k. At the instant when the kinetic energy of the block is equal to the potential energy of the spring, the spring is compressed a distance of: (A)\( v\sqrt{\frac{m}{2k}} \) (B)\( \frac{1}{2}mv^2 \) (C)\( \frac{1}{4}mv^2 \) (D)\( \frac{mv^2}{4k} \) (E)\( \frac{1}{4}\sqrt{\frac{mv}{k}} \)

6. A small disk of radius \( R_1 \) is fastened coaxially to a larger disk of radius \( R_2 \). The combination is free to rotate on a fixed axle, which is perpendicular to a horizontal frictionless table top, as shown in the overhead view below. The rotational inertia of the combination is I. A string is wrapped around the larger disk and attached to a block of mass m, on the table. Another string is wrapped around the smaller disk and is pulled with a force \( \overrightarrow{F} \) as shown in fig. below. The tension in the string pulling the block is: (A)\( \frac{mR_1F}{R_2} \) (B)\( \frac{mR_1R_2F}{I - mR_2^2} \) (C)\( \frac{mR_1R_2F}{I + mR_2^2} \) (D)\( \frac{mR_1R_2F}{I - mR_1R_2} \) (E)\( \frac{mR_1R_2F}{I + mR_1R_2} \)

相關試題

相關試卷