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Units 1-4 -- conceptual & math w/ previous test problems
What is the difference between average velocity and instantaneous velocity?
Average velocity is measured over a period of time; instantaneous is at one moment in time
How do you convert position, velocity, and acceleration graphs?
The slope of position-time (PT) is velocity; slope of velocity-time (VT) is acceleration, area under VT is displacement; area under acceleration-time (AT) is velocity
What is velocity on a position vs. time graph?
Slope
What is displacement on a velocity vs. time graph?
Area underneath
What kind of shape is seen on a position vs. time graph for positive acceleration? Negative?
Concave up parabola (positive); concave down parabola (negative)
What is the acceleration of a projectile at the top of its trajectory?
-9.8m/s² — or whatever it had previously been, assuming constant acceleration
For elevator problems, when will the Tension or Normal Force be larger than the Weight? Smaller? Equal?
When going up and accelerating, tension & Fn > weight; when accelerating down, Ft & Fn < weight; when constant Fn & Ft = weight
If 𝑥 ∝ 𝑡2 , what would happen to the magnitude of the x-variable once the t variable is tripled?
The magnitude will also triple because they are directly proportional
Suppose you have two variables R and T. Their relationship is such that 𝑇2 ∝ 𝑅3 What would happen to the T value once the R value is doubled?
T would increase by 2.83, the cube root of 8
What is the direction of the net force for things moving in uniform circular motion?
Towards the center of the circle — this is centripetal force
Where along a vertical circle would the net force not be towards the center?
At the very top; here it is aligned down with gravity
Why do astronauts feel weightless?
They are in a constant state of free fall around the Earth (the only force being gravity)
What are the conditions for an object to slow down? To speed up?
To speed up, the net force must increase; to slow down, the net force must decrease
What are the two things that affect the magnitude of friction experience by two rubbing objects?
Mass and the coefficient of friction
Does static friction have to exist if an object is stationary?
Yes
For a banked curve, which force is responsible applying the inward force?
The horizontal component of Fn/Fg
For a flat curve, which force is responsible for applying the inward force?
Centripetal force — this could be gravity, friction, tension, etc…
At what point in an object’s projectile trajectory will the velocity be at a minimum?
At the very top
At what point in an object’s projectile trajectory will the acceleration be at a minimum?
Acceleration is constant throughout
If two masses 𝑚1 and 𝑚2 , where 𝑚1 > 𝑚2 were to be in contact and pushed to the side, which scenario would provide the smaller contacting force between the two masses?
m2 contacting/pushing m1
What is the centrifugal force?
A perceived effect of objects traveling away from their circular path
For a satellite orbiting a larger mass, what would happen to the orbital period if you double the radial distance of the orbit?
It would quadruple (x4)
For an object moving in a circular path, how would the centripetal acceleration be affected if you doubled the velocity of motion and doubled the radius?
It would double (x2)
How do you determine the relationship between two variables?
Conducting experiments, collecting data, and analyzing how changes in one variable affect the other. This often involves plotting the data on graphs, calculating slopes, or using statistical methods.
Suppose you wanted to design an experiment to discover the relationship between normal force and friction force, what are some laboratory equipment items you could utilize?
Spring scale, varying surfaces, weight, & a friction block
If a meteor was to approach Earth, what would happen with its acceleration the closer it got to Earth?
It would increase due to a stronger gravitational pull
Is it possible to escape the influence of gravity completely within the observable universe?
No; however, you can get relatively close if you are completely alone in deep space
Why does a bullet dropped an a bullet fired land at the same time?
Gravity exerts the same force on them so they fall at the same rate, no matter their horizontal velocities
Of a fired bullet and a dropped bullet, which would hit the ground with a faster speed?
The fired bullet; it had a much higher initial (horizontal) velocity
If on a flat surface, at what angle should you launch a projectile to obtain the maximum range?
45 degrees
Suppose now that the starting point was higher than the landing point. Would it be launched at the same angle?
No, you’d want to use a smaller angle
How can you determine the angle of a banked curve?
Use arctan(v2/rg)
Are you stationary right now?
Yes and no — from my perspective I am but from the Earth’s I am moving very fast
If you wanted to drive a boat directly north across a river, but the river was flowing to the east, which direction would you have to aim the boat?
Northwest
What kind of friction is involved with walking?
Static friction
Note 
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