
The momentul of the system preserves:
Ok, we found the speed after the collision.
Now, because the impact is plastic, it produces heat, sound energy and who knows what other forms of energy. We denote all this wasted energy with

.
Now, we write the energy conservation law:

From the above equation, you find

, and then conclude that the sound energy can certainly not be greater than this.
Answer:
<em>Fx = 121.24lb</em>
<em>F = 140lb</em>
Explanation:
Since we are not given the angles subtended by the force, we can assume it to be 30 degrees.
The y component of the force expressed by the formula:
Fy = Fsintheta
Given the y-component of the force F to bee 70lb
70lb = Fsintheta
Get magnitude of the force
F = 70/sin theta
F = 70/sin 30
F = 70/0.5
F = 140lb
Get the x-component of the force
Fx = Fcos theta
Fx = 140cos 30
Fx = 140(0.8660)
Fx = 1,212.4lb
<em>Hence the x-component of the force sis 121.24lb</em>
<em></em>
<em>Note that the angle used was assumed. Other values can as well be used</em>
For the first part of the trip:
we have velocity = 960 km/hr and distance = 2250 km
velocity = distance / time
time1 = distance / velocity = 2250 / 960 = 2.34375 hours
For the second part of the trip:
we have velocity = 805 km/hr and distance = 1320 km
velocity = distance / time
time2 = distance / velocity = 1320 / 805 = 1.63975 hours
For the total trip:
we have:
total distance covered = 2250 + 1320 = 3570 km
total time taken = 2.34375 + 1.63975 = 3.9835 hours
average velocity = total distance / total time
average velocity = 3570 / 3.9835 = 896.1968 km/hr