This is the Doppler effect.
1. As the sound leaves the horn the sound waves are at first close to each other and as they move outwards they become further apart. The closer the sound waves are the louder the noise.
As the car gets the closer the sound waves get closer, so the horn becomes louder.
2. As the horn moves away, the sound waves become less frequent, causing the pitch to get lower.
Answer:you riding your bike at 12m/s
Explanation: this is because momentum P = mass x velocity. With a bigger mass and a velocity of about 12m/s, you really have a great momentum.
In order to find the force (F), you would have to use the formula for it:
F=ma
where m is mass and a is acceleration.
In the problem, the mass is 2.85kg and the acceleration is 4.9m/s^2.
Therefore,
F=2.85kg(4.9m/s^2)
F=13.965kg(m/s^2)
Since N=kg(m/s^2)
F=13.965N
And because the problem requires that we use only 2 significant figures,
F=13N
Therefore, the student must exert 13N of force.
