Density is mass over volume:

In your case, mass is 48 grams and volume is 12cm^3
If you put that into the equation, you will get your density:
Answer:
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Hi there!
(a)
Recall that:

W = Work (J)
F = Force (N)
d = Displacement (m)
Since this is a dot product, we only use the component of force that is IN the direction of the displacement. We can use the horizontal component of the given force to solve for the work.

To the nearest multiple of ten:

(b)
The object is not being displaced vertically. Since the displacement (horizontal) is perpendicular to the force of gravity (vertical), cos(90°) = 0, and there is NO work done by gravity.
Thus:

(c)
Similarly, the normal force is perpendicular to the displacement, so:

(d)
Recall that the force of kinetic friction is given by:

Since the force of friction resists the applied force (assigned the positive direction), the work due to friction is NEGATIVE because energy is being LOST. Thus:

In multiples of ten:

(e)
Simply add up the above values of work to find the net work.

Nearest multiple of ten:

(f)
Similarly, we can use a summation of forces in the HORIZONTAL direction. (cosine of the applied force)



Nearest multiple of ten:

Answer: 1.289 m
Explanation:
The path the cobra's venom follows since it is spitted until it hits the ground, is described by a parabola. Hence, the equations for parabolic motion (which has two components) can be applied to solve this problem:
<u>x-component:
</u>
(1)
Where:
is the horizontal distance traveled by the venom
is the venom's initial speed
is the angle
is the time since the venom is spitted until it hits the ground
<u>y-component:
</u>
(2)
Where:
is the initial height of the venom
is the final height of the venom (when it finally hits the ground)
is the acceleration due gravity
Let's begin with (2) to find the time it takes the complete path:
(3)
Rewritting (3):
(4)
This is a quadratic equation (also called equation of the second degree) of the form
, which can be solved with the following formula:
(5)
Where:
Substituting the known values:
(6)
Solving (6) we find the positive result is:
(7)
Substituting (7) in (1):
(8)
We finally find the horizontal distance traveled by the venom: