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.
The letter u before any unit means micro. Micro is a unit
prefix used in the metric system which actually means a factor of 10^-6 (one
millionth).
Now, 10^-6 is equivalent to a movement of 6 decimal places
from left to right. So to write the number 0.0000078 s into a number which has
a unit of us, therefore we move the decimal place by 6 to the right, giving us:
7.8 us
Another way to do this is to multiply the number by 1
million (1,000,000), so:
0.0000078 * 1,000,000
Using the calculator to solve, we get the value:
7.8 us
Answer:
It is wrong to say that "a single object all alone is moving" simply because it goes against Newton's law of inertia.
Explanation:
From Newton's law of inertia, it states that: An object at rest or in constant motion will continue in it's present state unless it is acted upon by an external force.
Which means that a single object by itself cannot move anywhere unless it is acted upon by an external force..
Thus, it is wrong to say that "a single object all alone is moving" simply because it goes against Newton's law of inertia.
