A small wooden block with mass m1 is suspended from the lower end of a light cord that is l long. The block is initially at rest
1 answer:
Answer:
Explanation:
The tension of the cord is not important, what matters is the height the block has risen.
When it has risen to its maximum it will have a speed of 0, and because of that it will have a kinetic energy of 0. However it will have a higher potential energy than it had at the beginning. The difference in potential energy will be:
The energy to rise the block with the bullet embedded into it came from the kinetic energy of the bullet.
These two energies are equal because all the kinetic energy the bullet had was transformed into potential energy. Therefore:
Rearranging:
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Answer:
Explanation:
For an object to move with constant velocity, the acceleration of the object must be zero:
.
As the net force equals acceleration multiplied by mass , this must mean:
.
So, the sum of the three forces must be zero:
,
this implies:
.
To obtain this sum, its easier to work in Cartesian representation.
First we need to define an Frame of reference. Lets put the x axis unit vector pointing east, with the y axis unit vector
pointing south, so the positive angle is south of east. For this, we got for the first force:
,
as is pointing north, and for the second force:
,
as is pointing west.
Now, our third force will be:
But, we need the magnitude and the direction.
To find the magnitude, we can use the Pythagorean theorem.
this is the magnitude.
To find the direction, we can use:
and this is the angle south of east.