Explanation:
ans ...(5,3)..............
The ball of a ballpoint pen is 0.5 mm in diameter and has an ASTM grain size of 12. How many grainsare there in the ball
1 answer:
Answer:
the number of grains in the ball is 274,848
Explanation:
Given that;
diameter = 0.5 mm
so radius r = 0.25 mm
first we determine the volume of the ball using the following equation;
V = 4/3×πr³
we substitute
V = 4/3×π(0.25)³
V = 0.06544 mm³
Now form table 1.1 "Grain sizes" a metal with grain size number of 12 has about 4,200,000 grains/mm³
so;
Number of grains N = 0.06544 × 4,200,000
N = 274,848 grains
Therefore, the number of grains in the ball is 274,848
You might be interested in
Answer:
The object will have an upward acceleration
Explanation:
Let's consider the forces applied on the box. We have only two forces:
- The applied force of push, , downward
- The force of gravity, , (also known as weight of the object), downward
Therefore, the net force on the box is:
Here, we know that force applied is equal or greater than the weight, so
And therefore the net force is greater than zero:
(1)
According to Newton's second law of motion, the net force on the box is equal to the product between its mass and its acceleration:
where
m is the mass of the box
a is its acceleration
Given (1), this means that
Therefore, the box will have an upward acceleration.
In this case force example we have:
So the mass of the box is
So the net force is
And the acceleration is