Q. A hiker shouts toward a vertical cliff 465 m away. The echo is heard 2.75 s later. (1) What is the speed of sound in air there? (2) The wavelength of the sound is 0.75m. What is the frequency of the wave? (3) What is its period?
Q. A car is travelling at a constant speed of 31.1 m/s on a highway. At the instant this car passes an entrance ramp, a second car enters the highway from the ramp. The second car starts from rest and has a constant acceleration. What acceleration must it maintain, so that the two cars meet for the first time at the next exit, which is 2.05 km away?