help for sat physics???

Test Preparation
1

<p>hey guys im taking the sat 2 physics test on january and i have some questions…i’ll appreciate it if you answer any at all…ihave a answers but i dont have the explanation! (btw this is the college board sat 2 book from like 1995)</p>

<li>A spaceship orbits the Earth at constant speed in a circular path. An astronaut inside the spaceship releases a ball, but the ball shows no tendency to move away from the astronaut’s hand. Which of the following best explains the behavior of the ball?</li>
</ol>

<p>d) the forceoof gravity exerted on the ball by the Earth is extremely weak due to the great distance of the spaceship from the Earth.
e) the force of gravity exerted on the ball by the Earth causes the ball to move in the smae circular path as the spaceship.
—why is the answer e, but not d?</p>

<li><p>In a darkened room, monochromatic light from the point source shown above passes through two very narrow slits in screen 1. which of the following best describes ithe interference pattern than it formed on screen 2?</p>

<pre><code> l ]
</code></pre></li>
<li><p>point source l ]
l (screen 1, there are slits) ] (screen 2, there are no space)
a) a set of bright concentric circles
e) a set of bright parallel bars parallel to the slits
—why is the answer e, but not a?</p></li>
<li><p>haelley’s comet is in an elliptical orbit about the sun and is visible from the earth once every 76 years. which of the following statements about the comet it true?</p></li>
</ol>

<p>d) the direction and the magnitude of the forceon the comet are always changing.
e) the direction of motion of the comet is always changing, but its speed is constant
----why is the answer d, but not e?</p>

<li><p>the speed with which sound waves in the air pass a stationary observer depends on the
a) speed of the air relative to the observer
b) speed of the source relative to the air
----why is the answer a, but not b?</p></li>
<li><p>two blocks of equal mass are attached to a string that passes over a frictionless pulley, as shown above, and are initially at rest with block a and height h1. a small mass m is placed on top of block a, causing it to move downward. when block a reaches height h2, the small mass m is lefted from block a. true statements about the motion of block a include which of the following?
I. it moves with constant velocity between heights h1 and h2.
II. it moves with constant acceleration between heights h1 and h2.
III. it comes to rest immediately after m is removed at height h2.
----------i chose the answer for I and III only but answer is II only,why?</p></li>
</ol>

<p>thank you a lot for helping me, good luck!</p>

2

<p>"1. A spaceship orbits the Earth at constant speed in a circular path. An astronaut inside the spaceship releases a ball, but the ball shows no tendency to move away from the astronaut's hand. Which of the following best explains the behavior of the ball?</p>

<p>d) the forceoof gravity exerted on the ball by the Earth is extremely weak due to the great distance of the spaceship from the Earth.
e) the force of gravity exerted on the ball by the Earth causes the ball to move in the smae circular path as the spaceship.
---why is the answer e, but not d?"</p>

<p>When you're orbiting the Earth and the ball doesn't seem to move, it's because it's orbiting at the same speed relative to the Earth. The force of gravity, obviously, is weaker but that doesn't explain why the ball seems to not move when you let go. Traveling at the same speed does.</p>

<p>Question 2: The answer is E and you would know this if you have read about those dual-slit interference patterns or have done experiments with them. The waves from each slit will have constructive interference (the bright lines) in some places but destructive interference (the spaces) in other places, alternating creating a pattern.</p>

<p>Question 3: This has to do with the law of periods. A comet in orbit will take the same time to travel every interval of an orbit regardless of the eccentricity (i think), so therefore when the comet nears the sun, it speeds up and orbits around it, but when its really far away, it slows down, all to keep the same time or distance traveled in a time interval (something like that).</p>

<p>Question 4: i think you might be thinking of how an ambulance's sirens sound like they're coming faster when in fact its only because the ambulance is moving towards you. The speed of the sound waves is still the same. However, if the speed of the air were to change, it would change the SPEED of the sound waves, not what you think their speeds are.</p>

<p>Sorry, question 5 is hard to answer without a diagram.</p>

3

<p>So, just wondering does the physics exam not have actual problems with numbers, where you need to formlas and stuff on it. Or do you just not have a problem with those types of problems involving formulas and doing claculations and stuff.</p>