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SI units
Measurement
Friction
Data Analysis
Kinematics
100
what are two advantages of the SI?
international communication and ease of conversion because the SI is a base 10 system
100
what is a measurement?
A measurement is a comparison between an unknown quantity and a standard
100
What does mu stand for?
The coefficient of friction. Stickiness. Usually between 0 and 1, the higher the number, the more friction.
100
What is the difference between standard deviation and a chi-reduced test?
Standard deviation is applied to numbers that are trying to measure the same thing (trials). It tells you how trustworthy an average is. The chi test is done to many averages, and tells you if your data matches a hypothesis (usually only do one per experiment)
100
How far will a car go if it accelerates at 5 m/s^2 for 10 seconds, and it starts from rest?
250 meters
200
How is the SI regulated? ( name the two organizations)
It is regulated by the International Bureau of Weights and Measures and the National Institute of Science and Technology.
200
What is the difference between accuracy and precision?
Accuracy is in reference to how close the value is to the correct or accepted value. Precision is in reference to how repeatable a value is.
200
What is the normal force, and how does it play in to the idea of friction?
The normal force is a reactionary force that points perpendicularly out of a surface that keeps the object from passing through the surface. The more normal force and object feels, the more friction resists motion.
200
Why do we use our standard deviations in the chi test?
Standard deviation gives you a picture of how much error you have at that level. Chi asks the question, "does this data point fit this hypothesis within the error of the experiment."
200
A Honda Civic is approaching a red light. A Ferrari is stopped at the red light. As soon as the Civic reaches the intersection the light turns green. If the civic was moving at 10 m/s and then pushes the accelerator to 4 m/s^2, and the Ferrari pushes the accelerator to 10 m/s^2. Who would win a 500 meter race?
The Ferrari gets there 3 seconds ahead.
300
What is a derived unit?
It is a combination of base units
300
What is two point calibration?
A method for checking the accuracy of an instrument
300
What is the static friction threshold on a 5 kg object sitting on a flat surface. The coefficient of static friction is 0.8. Why do we use the word "threshold?"
40N. Because that's the amount of force it takes to get the object moving, below that friction perfectly opposes any force.
300
Which one of these data sets has the best standard deviation:
Data Set 1 Data Set 2
3 5
1 7
3 6
15 10
What is Data Set 2 (0.9)
300
A spear is thrown at 30 degrees above level at 10 m/s. How long is it airborne, and how far does it go?
1 second, 8.66 meters.
400
convert 100 nm to kilometers
1 x 10^-10 km
400
What is a parallax?
The apparent shift in the position of an object when viewed from a different angle.
400
An object is being pushed on with a 500N force. The object has 50 kg of mass. The coefficient of static friction is 0.9. The coefficient of kinetic friction is 0.5. Will the object move? If so, with what acceleration?
Yes. 5 m/s^2
400
Two students design an experiment to test the effect of the mass of a ball on the time it takes to fall down the balcony. All of the balls they used have the same radius. Their data shows a slightly downward sloping line. What is the independent variable, dependent variable, controls, and why do they see a slightly downward sloping line?
IV=Mass
DV=Time to fall
Control=radius
Most likely the drag force on the lighter balls was greater, causing the times are lower mass to be slightly higher.
400
What speed will a projectile have in the y-direction 3 seconds after it is released at 45 m/s at 50 degrees? Is this on the first or second part of the arc?
4.5 m/s. Still in the first half, the y velocity would be negative on the second half.
500
What are the seven base units and the associated dimension
meter- length second- time temperature- kelvin amount of substance- mole luminous intensity - candela mass- kilogram electric current - ampere
500
correctly give the following measurement with the correct level of uncertainty.
25.7 +/- 0.25 cm
500
A matchbox car is loaded into a spring launcher. The spring has k=100N/m and is compressed 10cm. The car has mass 50g, and experiences a coefficient of static friction of 0.3. How far will the car go when the spring is released?
3.33 meters
500
Two students did an experiment about how the height of a drop effects the speed at which an object strikes the ground. Their data follows: 4.54
Height(m>Speed(m/s)
00
1
26.5
37.75
9
What hypothesis should the students try to fit to their data? Draw a graph of their data to see if your hypothesis makes sense.
v = sqrt(2gh)
500
What speed did yer scurvy cannon ball leave yer briny cannon if it reaches the merchant ship 20 meters away in 4 second?
20.6 m/s @ 76 degrees.