Which of the following is an example of the Doppler effect?
Vibrations from a tuning fork pass through the air and cause a nearby dish of
water to produce ripples of the same frequency.
Two identical musical instruments being played next to each other will produce a
sound twice as loud as if only one were played.
A hiker shouts "hello" into a canyon and hears it repeated back several times
before it fades away.
The siren of a police car sounds different when the car is coming toward you
than it does when it passes you.

The siren of police car sounds different when the car is coming towards you than it does when it passes you.

u can delete ur account.

1. go on google and write

2 open this and click on your profile pic and if your profile is not appearing, then u have to log in.

3. when u click on your profile pic, there appears four options on the top.

4. click on the 1st option and scroll down and go at the bottom.

5. click on edit profile.

6. there appears a option 'prefernces' and at that option at the right side , 'edit' is written.

7. click on the edit option.

8. there is a option " i want to delete my account" and click on that.

hope this u

and ur welcm

: )

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.