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3 years ago

Can someone help answer question 8?

Physics

2 answers:

tigry1 [53]3 years ago

5 0

Star A - (color) red-orange (type) main sequence

Star B - (color) yellow (type) supergiant

Star C - (color) blue-white (type) white dwarf

Star D - (color) yellow (type) main sequence

*im pretty sure these are correct if I remember clearly*

Liono4ka [1.6K]3 years ago

4 0

Answer:

A- Orange-main sequences

B- Red-red supergiant

C- White-White dwarf

D- Yellow-Red giant

Explanation: there's picture on the internet

'star types chart' 'star types and sizes'

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Constructive and destructive interference of vibrational waves on an aircraft can create a range of effects from a slight tail f

horrorfan [7]

Answer:

A. True

Explanation:

This is because these aircraft experiences different types of vibrations which include buffet vibrations and aerodynamic flutter. Buffet vibrations are vibrations caused by an interruption of airflow. Buffet vibrations are usually felt when the aerodynamic brakes are applied.

Aeroelastic flutter is the most dangerous type of vibration. This occurs when energy added to the wings due to airflow is greater than that lost due to damping. Aeroelastic flutter can cause aircraft to fail when the vibrations are large enough.

3 0

3 years ago

Explain two ways you could reduce the friction between two surfaces

abruzzese [7]

<span>A lubricant such as oil, grease, graphite powder can reduce the friction between two surfaces. Or using metal balls to space them and reduce the contact surface area as used in ball bearings.</span>

3 0

3 years ago

Which tools would sara us to find an irregularly shaped objects mass and volume A. a meter stick , a ruler , and water

tester [92]

I think it's D. Usually, to find the volume of an irregularly shaped object, you put it in water with a labeled beaker to measure how much the water rises. The balance would be used to measure the mass in grams.

4 0

3 years ago

A block weighing 400 kg rests on a horizontal surface and supports on top of it ,another block of weight 100 kg which is attache

Paladinen [302]

Answer:

$F_a=1470\ N$

Explanation:

<u>Friction Force</u>

When objects are in contact with other objects or rough surfaces, the friction forces appear when we try to move them with respect to each other. The friction forces always have a direction opposite to the intended motion, i.e. if the object is pushed to the right, the friction force is exerted to the left.

There are two blocks, one of 400 kg on a horizontal surface and other of 100 kg on top of it tied to a vertical wall by a string. If we try to push the first block, it will not move freely, because two friction forces appear: one exerted by the surface and the other exerted by the contact between both blocks. Let's call them Fr1 and Fr2 respectively. The block 2 is attached to the wall by a string, so it won't simply move with the block 1.

Please find the free body diagrams in the figure provided below.

The equilibrium condition for the mass 1 is

$\displaystyle F_a-F_{r1}-F_{r2}=m.a=0$

The mass m1 is being pushed by the force Fa so that slipping with the mass m2 barely occurs, thus the system is not moving, and a=0. Solving for Fa

$\displaystyle F_a=F_{r1}+F_{r2}.....[1]$

The mass 2 is tried to be pushed to the right by the friction force Fr2 between them, but the string keeps it fixed in position with the tension T. The equation in the horizontal axis is

$\displaystyle F_{r2}-T=0$

The friction forces are computed by

$\displaystyle F_{r2}=\mu \ N_2=\mu\ m_2\ g$

$\displaystyle F_{r1}=\mu \ N_1=\mu(m_1+m_2)g$

Recall N1 is the reaction of the surface on mass m1 which holds a total mass of m1+m2.

Replacing in [1]

$\displaystyle F_{a}=\mu \ m_2\ g\ +\mu(m_1+m_2)g$

Simplifying

$\displaystyle F_{a}=\mu \ g(m_1+2\ m_2)$

Plugging in the values

$\displaystyle F_{a}=0.25(9.8)[400+2(100)]$

$\boxed{F_a=1470\ N}$

8 0

3 years ago

In order to slide a heavy desk across the floor at constant speed in a straight line, you have to exert a horizontal force of 40

san4es73 [151]

Answer:

F = f from Newton’s first law.

Explanation:

since the desk is moved in a straight line at a constant speed, newton first law tell us that the two forces must be equal.

Newton's First Law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. since the table has been set in motion by the 400 N force, it will remain in motion unless it is been acted upon by an external force, and this means that the 400 N must be equal to the frictional force for it to have been in motion in the first instance.

3 0

3 years ago