Relative speed of Tina with respect to David is given by



now the acceleration of Tina with respect to David



now the relative displacement would be zero when Tina cross David
so now we have



now the speed of Tina at this moment is given as



<em>so the speed will be 52 m/s</em>
Earth would have different climates and would be more colder.
The correct option is C.
According to the safety tips that is usually released by the government, it is typically advised that during a tornado, that people should go to the interior room on the lowest base of their houses, the room should be windowless. When in this room, it is advisable that one should get under a furniture that can not be easily damage and then use one's arms to protect the head and the neck.
<span>Human ear can hear the lowest frequency about 20 Hz, this is 20 vibrations per second. Vibrations of pendulum are very small and frequency is less than 20 Hz, so we can't hear it.</span>