Answer to Question #268982 in Classical Mechanics for Kdueiwowlls

Question

Consider the following:

If two equal mass objects have the same net force acting on them, then they will be experiencing the same change in speed.

(a) Is this statement valid?

(b) If you contend the statement is valid, how do you know?

(c) If you contend the statement is invalid, what is wrong with it?

(d) If the statement is invalid, restate it to give a valid statement.

(e) Is the valid statement (original, or your revision) a conditional or bi-conditional? How do you know?

(f) Would the following investigation test, i.e. provide data to either support or contradict, the valid hypothesis (either the original or your revision), or will it fail to test the hypothesis? Explain.

A person runs a ski mobile on a frozen lake varying how the speed changes during the runs for 24 trials and measures the net force that acts on the ski mobile. Each time she finds if the speed changes there is net force.

Answer 1

(a) Valid

(b) By Newton's second law: the statement says "equal mass" and "the same force", which means that the result of $\vec a=\vec F/m$ is the same.

(c) Nothing wrong, I think it is valid.

(d) Nothing wrong, I think it is valid.

(e) It is bi-conditional because it contains two statements, about mass and force.

(f) The hypothesis is wrong because it refers to only one body.