(a) The ball's height <em>y</em> at time <em>t</em> is given by
<em>y</em> = (20 m/s) sin(40º) <em>t</em> - 1/2 <em>g t</em> ²
where <em>g</em> = 9.80 m/s² is the magnitude of the acceleration due to gravity. Solve <em>y</em> = 0 for <em>t</em> :
0 = (20 m/s) sin(40º) <em>t</em> - 1/2 <em>g t</em> ²
0 = <em>t</em> ((20 m/s) sin(40º) - 1/2 <em>g t</em> )
<em>t</em> = 0 or (20 m/s) sin(40º) - 1/2 <em>g t</em> = 0
The first time refers to where the ball is initially launched, so we omit that solution.
(20 m/s) sin(40º) = 1/2 <em>g t</em>
<em>t</em> = (40 m/s) sin(40º) / <em>g</em>
<em>t</em> ≈ 2.6 s
(b) At its maximum height, the ball has zero vertical velocity. In the vertical direction, the ball is in free fall and only subject to the downward acceleration <em>g</em>. So
0² - ((20 m/s) sin(40º))² = 2 (-<em>g</em>) <em>y</em>
where <em>y</em> in this equation refers to the maximum height of the ball. Solve for <em>y</em> :
<em>y</em> = ((20 m/s) sin(40º))² / (2<em>g</em>)
<em>y</em> ≈ 8.4 m
The appropriate answer is 4. The formation of Mid-Ocean ridges. There are two types of divergent margins: continental separation and oceanic floor spreading. Where the sea floor separates magma upwells and new oceanic crust is formed. Mid ocean ridges are home to hydrothermal vents. These support a unique ecosystem of marine organisms. The Mid- Atlantic Ridge where the African and Eurasian plates separate from the North and South American plates.
Answer: 100 suns
Explanation:
We can solve this with the following relation:

Where:
is the diameter of a dime
is the diameter of the Sun
is the distance between the Sun and the pinhole
is the amount of dimes that fit in a distance between the sunball and the pinhole
Finding
:


This is roughly the diameter of the Sun
Now, the distance between the Earth and the Sun is one astronomical unit (1 AU), which is equal to:

So, we have to divide this distance between
in order to find how many suns could it fit in this distance:

Te direction of the magnetic force for the velocity of the proton in the
-ve y direction will be +ve z direction.
As we know that the right-hand rule is based on the relation of magnetic fields and the forces that they exert on moving charges.When a charged particle moves under a magnetic field, it exerts a force on the particle, which is not in the same direction but different than the direction of the magnetic field.Under the right-hand rule, if we point our pointer finger in the direction of the charged particle is moving and the middle finger is representing the direction of the magnetic field then our thumb depicts the direction of the magnetic force which is exerted on the charged particle.
So, we are given that the direction of the velocity of the proton is in the negative y direction and the direction of the magnetic field is in the positive x direction, so the magnetic force is acting in the positive z direction.
To know more about the right-hand rule refer to the link brainly.com/question/9750730?referrer=searchResults.
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No because they could be different materials for example one could be concrete and one could be aluminium