During a school experiment, students count 1500 vibrations of a bell in a time interval of 30s.
(a) Determine the frequency of the bell.
(b) Calculate the time period of one vibration.
(c) After the bell is repaired, it is found to vibrate 10% faster than before. Find the new frequency and the new time period.
(d) How many more vibrations will the repaired bell make in one minute compared with the unrepaired bell?