A tire has a tread pattern with a crevice every 2.00 cm. Each crevice makes a single vibration as the tire moves. What is the frequency of these vibrations if the car moves at 30.0 m/s?

Frequency of the vibration due to crevice is 1500 Hz.

Explanation:

Frequency is defined as rate of vibration per second. Its S.I. unit is s⁻¹ or Hz.

According to the problem, we have to find number of crevice car makes in 1 second.

Speed of car, u = 30 m/s

Distance covered by car in 1 second, d = 30 m

For every 0.02 m, one crevice occurred by the tire of car.  

Number of crevice occurred in 1 second by the car =  

                                                                                    = 1500

Since, each crevice makes a single vibration. Thus, the frequency of these vibrations is 1500 Hz.

the answer is neither ball has a charge.

because if they were both positively charged, they will repel each other.

if they were positively and negatively charged, they will seek.