9. A0.9 kg block is attached to an unstretched spring with a spring constant of 10 N/m The block is released from rest. How long does it take for the block to return to its initial position (1.e. what is its period)? A. 0.3pi s B 0.5pi s C.0.6m s D.0.9m s 10. A student wishes to determine the spring constant of a spring in a mass-spring oscillating system. Which of the following pieces of equipment will provide the measured quantities needed for this calculation? Select two answers. A. Meterstick B. Balance C. Stopwatch D. Accelerometer

9. To find the period of the block attached to the spring, we can use the formula for the period of a simple harmonic oscillator:<br /><br />T = 2π√(m/k)<br /><br />where T is the period, m is the mass of the block, and k is the spring constant.<br /><br />Given:<br />Mass of the block (m) = 0.9 kg<br />Spring constant (k) = 10 N/m<br /><br />Substituting the values into the formula:<br /><br />T = 2π√(0.9 kg / 10 N/m)<br />T = 2π√(0.09 kg·m/N)<br />T = 2π√(0.09 s²)<br />T = 2π(0.3 s)<br />T = 0.6π s<br /><br />Therefore, the correct answer is B. 0.5π s.<br /><br />10. To determine the spring constant of a spring in a mass-spring oscillating system, the student needs to measure the mass of the attached object and the period of the oscillation. The equipment needed for this calculation are:<br /><br />A. Meterstick: This is not necessary for this calculation, as the distance traveled by the block is not required.<br /><br />B. Balance: This is necessary to measure the mass of the attached object.<br /><br />C. Stopwatch: This is necessary to measure the period of the oscillation.<br /><br />D. Accelerometer: This is not necessary for this calculation, as the acceleration of the block is not required.<br /><br />Therefore, the correct answers are B. Balance and C. Stopwatch.