Physics

physicsAP10005 Physics I

Tutorial 7 (Chapters 17, 18)

1. (17P11) A flower pot is knocked off a window ledge from a height d = 20.0 m above the sidewalk as shown in the figure below. It falls toward an unsuspecting man of height h =1.75 m who is standing below. Assume the man requires a time interval of Δt = 0.300 s to respond to the warning. How close to the sidewalk can the flower pot fall before it is too late for a warning shouted from the balcony to reach the man in time?

2. (17P15) A hammer strikes one end of a thick iron rail of length 8.50 m. A microphone located at the opposite end of the rail detects two pulses of sound, one that travels through the air and a longitudinal wave that travels through the rail. (a) Which pulse reaches the microphone first? (b) Find the separation in time between the arrivals of the two pulses.

3. (17P16) A rescue plane flies horizontally at a constant speed searching for a disabled boat. When the plane is directly above the boat, the boat’s crew blows a loud horn. By the time the plane’s sound detector receives the horn’s sound the plane has travelled a distance equal to half its altitude above the ocean. Assuming it takes the sound 2.00 s to reach the plane, determine (a) the speed of the plane and (b) its altitude.

4. (17P40) A block with a speaker bolted to it is connected to a spring having spring constant k and oscillates as shown in the figure below. The total mass of the block and speaker is m, and the amplitude of this unit's motion is A. The speaker emits sound waves of frequency f. (Use any variable or symbol stated above along with the following as necessary: v for the speed of sound.)

a. Determine the highest frequency heard by the person to the right of the speaker.

b. Determine the lowest frequency heard by the person to the right of the speaker.