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liraira [26]
3 years ago
14

In 1986, several robotic spacecrafts were sent into space to study the Halley's Comet. Which of these statements best explains w

hy humans should continue to send robotic spacecrafts into space?
a. They absorb harmful radiations in space.
b. They help change weather conditions on Earth.
c. They help discard some myths about objects in space.
d. They destroy meteors and comets which might strike Earth.
Physics
1 answer:
Archy [21]3 years ago
8 0
<span>c. They help discard some myths about objects in space.

When we learn something new, then we know more stuff,
and that helps us avoid ignorance and superstition.

The REAL question is:  
</span><span>Why should we continue to send robotic spacecrafts,
and NOT spacecrafts piloted by people ?</span>
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A test rocket is launched vertically from ground level (y = 0 m), at time t = 0.0 s. The rocket engine provides constant upward
SVETLANKA909090 [29]
The important thing to note here is the direction of motion of the test rocket. Since it mentions that the rocket travels vertically upwards, then this motion can be applied to rectilinear equations that are derived from Newton's Laws of Motions.These useful equations are:

y = v₁t + 1/2 at²
a = (v₂-v₁)/t

where
y is the vertical distance travelled
v₁ is the initial velocity
v₂ is the final velocity
t is the time 
a is the acceleration

When a test rocket is launched, there is an initial velocity in order to launch it to the sky. However, it would gradually reach terminal velocity in the solar system. At this point, the final velocity is equal to 0. So, v₂ = 0. Let's solve the second equation first.

a = (v₂-v₁)/t
a = (0-30)/t
a = -30/t

Let's substitute a to the first equation:
y = v₁t + 1/2 at²
49 = 30t + 1/2 (-30/t)t²
49 = 30t -15t
49 = 15 t
t = 49/15
t = 3.27 seconds

3 0
3 years ago
5. Forces have
Verdich [7]

5)

In physics, forces are interactions that are able to change the velocity of an object.

Force is a vector quantity, so it has a magnitude and a direction.

The SI units of the force is the Newton (N).

Whenever an unbalanced force is applied to an object, the object experiences an acceleration, according to Newton's second law of motion:

F=ma

where

F is the force

m is the mass of the object

a is its acceleration

So, the acceleration of an object is proportional to the force applied:

a=\frac{F}{m}

6)

In physics, arrows are used to represent vector quantities. Therefore, they are also used to represent forces.

In particular, when a vector quantity is represented by an arrowr:

- The length of the arrow is proportional to the magnitude of the vector quantity

- The direction of the arrow corresponds to the direction of the vector quantity

Therefore, if a force is represented through an arrow:

- The length of the arrow shows the strength (magnitude) of the force

- The direction of the arrow shows the direction of the force

7)

As we said in part 5), the SI units of the force is the Newton (N).

We can rewrite the Newton in terms of fundamental units only. We can do it starting from the equation:

F=ma

where

F is the force

m is the mass

a is the acceleration

- The mass is measured in kilograms (kg)

- The acceleration is measured in meters per second squared (m/s^2)

Therefore, 1 N corresponds to:

[N]=[kg][\frac{m}{s^2}]=[kg\cdot m \cdot s^{-2}]

B)

Gravity is an attractive force that exists between all objects that have mass. See more explanations about gravity in part 4).

3)

Mass is a scalar quantity; it gives us a measure of the "amount of matter" contained in an object.

The SI unit of the mass is the kilogram (kg).

Being a scalar, mass has no direction, but only a magnitude.

Moreover, the mass is an intrinsec property of an object: therefore, it does not depend on the location of the object. So, an object has always the same mass, either it is on Earth or on another planet.

On the other hand, the force of gravity on an object depends on its location, so it changes.

4)

As we said in part 3), gravity is an attractive force that exists between all objects that  have mass.

The magnitude of the force of gravity between two objects is given by the Universal Law of gravitation:

F=\frac{Gm_1 m_2}{r^2}

where

G is the gravitational constant

m1, m2 are the masses of the two objects

r is the separation between the objects

From the equation above, we observe that:

- all objects are attracted to one  another with a gravitational force that is proportional to the mass of the objects  and inversely proportional to the square of the distance between them.

And so:

a. When the mass of one or both objects increases, the gravitational force between  the objects increases

b. When the distance between two objects increases, the attraction between the  objects decreases

7 0
3 years ago
In a displacement/time graph the slope of the line is equal to the ________.
mamaluj [8]
In a displacement/time graph, the slope of the line is equal to the velocity
3 0
3 years ago
The doctor writes a prescription for na heparin 20,000 units in 500 ml n.s. infuse over 8 hours. what is the flow rate in ml/hr?
Ne4ueva [31]
I think this type of equation could be conducted in simple division equation since it does not involve drop rate.

we know that there is 500 ml of substance and should be infused within 8 hours period.

So the flow rate in ml/hr would be: 

500/8 = 62.5 ml/hr                                                                                    
8 0
2 years ago
Two resistors with values of 6.0 ohms and 12 ohms are connected in parallel. This combination is connected in series with a 2.0
ivanzaharov [21]

Answer:

4A

Explanation:

According to ohm's law;

E = IRt where;

E is the source voltage = 24volts

I is the total current flowing in the circuit = ?

Rt is the total effective resistance in the circuit.

To find Rt, we will resolve the resistors in parallel first.

Since 6ohms and 12ohms resistors are in parallel, their effective resistance will give;

1/R = 1/6+1/12

1/R= 2+1/12

1/R = 3/12

3R = 12

R = 4ohms.

This resistor will now be in series with the 2.0ohms resistor to finally have;

Rt = 4+2

Rt = 6ohms

From the ohms law formula;

I = E/Rt

I = 24/6

I = 4Amperes

The total current in the circuit is 4A

This same currents will flow in the 2ohms resistor since same current flows in a series connected resistors.

3 0
3 years ago
Read 2 more answers
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