Answer:
The pitch that he hears after the truck passes and is moving away is 819.6 Hz.
Explanation:
The pitch that he hears after the truck passes and is moving away can be calculated using the following equation:

Where:
: is the perceived frequency
: is the emitted frequency
: is the speed of sound = 340 m/s
: is the speed of the observer = 0 (he is not moving)
: is the speed of the fire truck
First, we need to find the speed of the fire truck. When it approaches the observer we have:




Hence, the speed of the fire truck is 25.05 m/s.
Now, we can calculate the pitch that the observer hears after the truck passes:



Therefore, the pitch that he hears after the truck passes and is moving away is 819.6 Hz.
I hope it helps you!
#1
Since Beth rode the Flying saucer ride which is spinning on its axis while axis is moving to and fro as well, so here Beth will experience two motions in this case
(i) Spinning motion
(ii) Rotational motion
#2
Jill and Scott both traveled for 30 min
So time of motion for both is 0.5 h as we know that 1 h = 60 min
Now from the formula of speed we know that

Speed of Jill

speed of Scott

so correct answer is
B) Scott had the faster speed since he rode at 20 k/h while Jill only traveled 10 km/h.
#3
Since we know that <em>acceleration is rate of change in velocity</em>
So here we can say that every motion where velocity changes with time then it is an accelerated motion.
Now change in velocity occurs when either the magnitude will change or its direction will change because here velocity is a vector quantity and it will change with magnitude and direction both.
so here due to oval path the direction of velocity will changes at many points and hence it will be an accelerated motion.
so correct answer is
<em>C) James was right since the car changed direction during the race.</em>
A. Equal and opposite forces
Explanation:
History law states that for every action (force) in nature there is an equal and opposite reaction. In other words, if object A exerts a force on object B, then object B also exert an equal and opposite force on object A