calculate the frequency and time period of sound wave of 35 m wave length propagating at a speed of 3500m/s​

According to the tide table below what time of day will the highest tide occur?

What do you think car designers do if the damage caused by a crash test is too severe?

Alead ball is dropped into a lake from a diving board 5m above the water . it hits the water with a certain velocity and then sink with constant velocity in bottom . it reaches the bottom 5 second after it is dropped if g= 10m/s2 . find depth of the lake and average velocity of the ball ?