Q. A 465 g ball swings in a vertical circle at the end of a 1.3 m-long string. When the ball is at the bottom of the circle, the tension in the string is 21 N. What is the speed of the ball at that point?
Q. A tuning fork produces a sound with a frequency of 249 Hz and a wavelenght in air of 1.35 m. What value does this give for the speed of sound in air? Answer in units of m/s.