A pendulum was set up and measurements were made to enable the mechanical energy to be calculated at the start position S and the lowest point of the pendulums swing L.

The mass of the pendulum bob was determined on an electronic scale and its diamter was measured using calipers. The initial height was measured with a meter stick. At the lowest point of its swing, the pendulum bob broke a photogate light beam. The time interval that the light was interrupted was recorded on an electronic timer attached to the photogate.
Use the following data to complete a report.
MAss of pendulum bob = 240.3 g
Diameter of pendulum bob = 3.50 cm
Initial height of pendulum bob = 48.0 cm
Length of pendulum string = 2.14 m
Time interval of photogate light interruption = 11.8 ms

Your report should include the following:
(a) conclusion as to whether or not the pendulum demonstrated the law of conservation of energy
(b) calculations of the efficiency of the pendulum as a mechanical machine

I am really confused how to even start this question. I think that I should figure out the Emechanical = Ek + eg

=1/2(240.3)(0) + 240.3(9.8)(.48)
=1130.37J

but have no idea how to calculate the speed of when it hit. I don't know where to go from here at all, please help!

The clue is the diameter of the bob

it broke the beam for 11.8 *10^-3 seconds
it is .035 meters in diameter
so it went
.035 meters in 11.8^10^-3 seconds
which is about 2.97 meters/s

(1/2) 240.3 v^2 = gh = 1130.37

v^2 = 9.407
v = 3.067 ideally but we only measured 2.97 m/s so some energy got lost along the way like air friction and stuff.

(1/2) 240.3 v^2 = mgh = 1130.37

v^2 = 9.407
v = 3.067 ideally but we only measured 2.97 m/s so some energy got lost along the way like air friction and stuff.

To calculate the speed of the pendulum bob at the lowest point of its swing, you can use the principle of conservation of mechanical energy. According to this principle, the total mechanical energy of the system remains constant throughout the pendulum's motion. The mechanical energy (E) can be expressed as the sum of the kinetic energy (Ek) and the gravitational potential energy (eg) of the pendulum.

Since the initial kinetic energy of the pendulum bob is zero (as it starts from rest), we only need to consider the gravitational potential energy at the start position (S) and the lowest point (L) of the swing.

The formula for gravitational potential energy is given by eg = mgh, where m is the mass, g is the acceleration due to gravity, and h is the height.

(a) Calculating the gravitational potential energy at the start position:
eg(start) = m(start) * g * h(start)
eg(start) = 0.2403 kg * 9.8 m/s^2 * 0.48 m

(b) Calculating the gravitational potential energy at the lowest point:
eg(lowest) = m(lowest) * g * h(lowest)
eg(lowest) = 0.2403 kg * 9.8 m/s^2 * 0 m

The change in gravitational potential energy between the start and lowest point of the pendulum's swing is given by:
Δeg = eg(lowest) - eg(start)

The change in gravitational potential energy is equal to the kinetic energy at the lowest point:
Δeg = Ek(lowest)

Since the efficiency (Eff) of the pendulum is defined as the ratio of useful work done to the total energy input, we can calculate it using the following formula:
Efficiency = (Ek(lowest) / Emechanical) * 100%

Substituting the calculated values, you can find the conclusion as to whether or not the pendulum demonstrates the law of conservation of energy and calculate the efficiency of the pendulum as a mechanical machine.