Wave Speed (AP1)

Wave Speed (AP1)
1. Transverse waves with a speed of 50.0 m/s are to be produced on a stretched string. A 5.00 m length of
string with a total mass of 0.060 kg is used. What is the required tension in the string? (30.0 N)
2. A person on a pier observes a set of incoming waves with a distance of 1.6 m between crests. A wave laps
against the pier every 4.0 s.
a. What is the frequency of the waves?
b. What is the speed of the waves? (0.40 m/s)
3. If one end of a heavy rope is attached to one end of a lighter rope, the speed of the wave will change as the
wave goes from the heavy rope to the light one.
a. Will the speed increase or decrease? Why?
b. What happens to the wavelength? Why?
4. If you stretch a rubber hose and pluck it, you can observe a pulse traveling up and down the hose.
a. What happens to the speed of the pulse of you stretch the hose more tightly? Why?
b. What happens to the speed if you fill the hose with water? Why?
5. Sonic Sal sings toward a cliff in the mountains and his sound is reflected directly back to him. He is standing
170 m from the natural wall. If his sound is traveling through air at 340 m/sec through the air, how long will
it take Sal to hear his own echo? (1.0 sec) (HINT: Draw the picture)
6. A sonar generator on a submarine produces periodic ultrasonic waves at a frequency of 2.50 MHz. The
wavelength of the waves in seawater is 4.80x10-4 m. When the generator is directed downward, an echo
reflected from the ocean floor is received 10.0 s later. How deep is the ocean at this point? (Assume that
wavelength is constant at all depths) (6.00 km)
7. One end of a string is fixed to a wall. The other end hangs over a
pulley and was a block of mass 2.00 kg attached to the other end.
The horizontal part has a length of 1.60 m and a mass of 20.0 g. What
is the speed of the transverse pulse on the string? (39.6 m/s)
- - - - - REVIEW - - - - 8. A 0.030 kg projectile moving with a velocity of 300.0 m/s strikes a 2.00 kg block at rest on a 1.00m high post.
The projectile passes through the block emerging on the other side with a velocity of 100.0 m/s.
a. What is the velocity of the block after the impact? (3.00m/s)
b. How far from the base of the post will the block be when it
impacts the ground? (1.36m)
c. What percent of kinetic energy of the block/projectile system remains after the collision? (11.8%)
d. What are three reasons for this change in kinetic energy?