Speed is scalar, meaning it's only going to be like 74 mph, doesn't matter which direction. Velocity is a vector, meaning it has direction. You can go -74mph when talking about velocity, not speed.
Answer:
v = 79.2 m/s
Solution:
As per the question:
Mass of the object, m = 250 g = 0.250 kg
Angle, 
Coefficient of kinetic friction, 
Mass attached to the string, m = 0.200 kg
Distance, d = 30 cm = 0.03 m
Now,
The tension in the string is given by:
(1)
Also
T = m(g + a)
Thus eqn (1) can be written as:





Now, the speed is given by the third eqn of motion with initial velocity being zero:

where
u = initial velocity = 0
Thus


Periodic motion implies that the ride oscillates back and forth. The period is the time it takes to complete one cycle. Therefore it would be the swing.