Question

You pull a simple pendulum of length 0.240m to the side through an angle of 3.50° and release it. a) How much time does it take the pendulum bob to reach its highest speed? b) How much time does it take if the pendulum bob is released at an angle of 1.75° (instead of 3.50°)?

Answer 1

Answer:

See explanation

Explanation:

This is simple and can be solved using kinetic and potential energy.

At the lowest point the speed is the greatest and all potential energy became kinetic.

So, $E_{kinetic}= \frac{mV^{2} }{2}$

and $E_{potential}= mgh$

$E_{kinetic}=E_{potential}$, therefore

$\frac{mV^{2} }{2}= mgh$

m goes away, and $V=\sqrt{2gh}$, where g is 9.81, the only thing is missing is h.

h is the height at which the pendulum starts.  Given that L is 0.240m, we calculate it by doing the following: $h = L - L*cos(\alpha) = L (1-cos(\alpha))$

Now, get the calculator, get h, then get V.

Good luck!