Physics I Lab Final

Write/identify a testable hypothesis

“IV is related to DV”

“As IV increases, DV will decrease”

Understand what is meant by a true value.

the actual value or measurement of something that likely falls within a range of values

Know how to determine measurement uncertainties either from the reading of a measuring device or the use of standard deviation

uncertainty from reading a measurement: ± half of the smallest unit of measurement or ±1 in the least significant digit for digital instruments (ex: for a ruler using cm, it would be ±0.5cm or ±0.05m, for a ruler with mm it would be ±0.5mm or ±0.05cm or ±0.005 m) (ex: for a digital caliper that reads 41.44mm, it would be ±0.01mm)

standard deviation: the lower the STD, the more precise your measurements are.

Random vs systematic errors

Random: fluctuations in measurements due to the device or technique. These are “two-sided” such that repeated measurements have an equal chance of lying above or below the true value (Ex: Estimating the last digit on a meter stick or timing with a stopwatch)

Systematic: “one-sided” and consistently favor values higher or lower than the true value (Ex: A mis-calibrated scale)

Causation vs correlation

Causation means one variable directly influences another and there is an underlying mechanism and it is establish by: 1. the absence of other influential factors, and 2. making sure one event precedes the other.

correlational means variables change together but they do not cause one another. these studies collect data without manipulating variables which is done in experimental studies and focuses on observing
natural associations between variables

Identify the assumptions in a provided experimental design

it is assumed that measurements are taken accurately, variables were kept controlled, each trial was independent from each other, that the physical theory is correct.

assumptions should be relevant to the experiment (Ex. measuring the acceleration due to gravity, assume air resistance is negligible unless it is being measured.)

Relationship between Inertia and torque, and predict how much relative force is needed to change the rotational motion of objects of different shapes and mass

• inertia is the resistance to change in motion

• torque is the force that causes the rotation

• with the same angular acceleration:

  • larger radius: inertia increases, more force/torque required

  • smaller radius: inertia decreases, less force/torque required

  • larger mass: inertia increases, more force/torque required

  • smaller mass: inertia decreases, less force/torque required