Answer:
a = 12 [m/s²]
Explanation:
To solve this problem we must use Newton's second law which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
ΣF = m*a
where:
ΣF = sum of forces acting on a body [N] (units of Newtons)
m = mass = 0.5 [kg]
a = acceleration [m/s²]
Let's take the direction of positive forces to the right and negative forces directed to the left
2 + 8 - 4 = 0.5*a
6 = 0.5*a
a = 12 [m/s²]
The correct answer for the question that is being presented above is this one: "Schmidt-Cassegrain focus." A focal arrangement that has a thin lens that the light passes through before traveling down the tube to the objective mirror is a Schmidt-Cassegrain focus.
Here are the following choices:
a. Cassegrain focus
b. Newtonian focus
c. Schmidt-Cassegrain focus
<span>d. Schmidt focus</span>
Answer:

Explanation:
One of the first propulsion characteristics given in the example is that all engines are equal.
In this way if we have 4 engines running at the same time, it means that its capacity is 100%.
Under this premise, if 100% is found, the Jet is capable of reaching a speed of 8.7m / s ^ 2.
However, the question is, what would happen if 2.4 "Engines" now work.
To do this then we make a simple equivalence,
If 4 engines is the equivalent of 100%, when would it be 2.4 engines?

In this way it would mean that the body could be driven to 60% of its total.
So

Answer:
3600 kg
Explanation:
From the question,
Density = Mass/Volume
D = M/V.............................. Equation 1
Where D = Density of the substance, M = mass of the substance, V = Volume of the subtance.
Make M the subject of the equation
M = D×V ............................ Equation 2
Given: D = 1200 kg/m³, V = 3 m³.
Substitute these values into equation 2
M = 1200×3
M = 3600 kg.
Hence the mass of the substance is 3600 kg