sorry i did not mean to answer
To enable life, this most special of attributes, planet earth has a number of ideal features it is unique among other planets in our solar system for having water in its liquid form at the surface in an conducive to life evolving
Answer: velocity of the car is 113.33m/s
Explanation:
From Doppler effect,
in the case which the source is moving towards the observer at rest
f2 = v/(v-vs) *f1
where f2 is the final observed frequency
f1 is the initial observed frequency
v = 340m/s (speed of sound in air)
vs = velocity of the source of sound.
rearranging the above equation
f2*(v - vs) = f1* v
vs = (f1* v/f2) - v
but f1 = 80Hz
f2 = 60Hz
v = 340m/s
substituting,
vs = (80 x 340)/60 - 340
vs = 453.33 - 340
vs = 113.33m/s
velocity of the car is 113.33m/s
Since both hv same mass and elsstic collision, so their velocity will exchange. Bob A will stop and bob B will move with speed of A just before the collision.
Speed will be = squreroot ( 2*g*L)
L is length of pendulum
it cannot be reuse and replaced for long period of time.hope it helps u
