IB Physics SL 6.4.2 Designing investigations

[Maximum number: 1]

A student studies the relationship between the centripetal force applied to an object undergoing circular motion and its period T.
The object (mass m ) is attached by a light inextensible string, through a tube, to a weight W which hangs vertically. The string is free to move through the tube. A student swings the mass in a horizontal, circular path, adjusting the period T of the motion until the radius r is constant. The radius of the circle and the mass of the object are measured and remain constant for the entire experiment.

Figure for Question IB Physics SL S2.1.2 Designing Investigations Questions question 1 — IB Physics SL

The student collects the measurements of T five times, for weight W. The weight is then doubled ( 2 W ) and the data collection repeated. Then it is repeated with 3 W and 4 W. The results are expected to support the relationship

W=\frac{4 \pi^{2} m r}{T^{2}}

State why the experiment is repeated with different values of W.

In reality, there is friction in the system, so in this case W is less than the total centripetal force in the system. A suitable graph is plotted to determine the value of m r experimentally. The value of m r was also calculated directly from the measured values of m and r.

In order to draw a graph« of W versus $\frac{1}{\mathrm{~T}^{2}}$ »

OR

to confirm proportionality between « W and $T^{-2}$ »

OR

to confirm relationship between « W and T »

OR

because W is the independent variable in the experiment

OWTTE.

IB Physics SL S2.1.2 Designing Investigations Questions question 1