Answer
given,
diameter of the pipe is = (14 ft)4.27 m
minimum speed of the skater must have at very top = ?
At the topmost point of the pipe the normal force will be equal to zero.
F = mg
centripetal force acting on the skateboard
equating both the force equation
r = d/2 = 14/ 2 = 7 ft
or
r = 4.27/2 = 2.135 m
g = 32 ft/s² or g = 9.8 m/s²
v = 14.96 ft/s
or
v = 4.57 m/s
Complete question:
A pendulum of length L = 48.5 cm and mass m = 169 g is released from rest when the cord makes an angle of 65.4° with the vertical. What is the speed of the mass (m/s) upon reaching its lowest point?
Answer:
The speed of the mass upon reaching its lowest point is 2.36m/s
Explanation:
To obtain the speed of the mass upon reaching its lowest point, we apply the principle of conservation of mechanical energy. At the lowest point, the kinetic energy of the pendulum is maximum and at the highest point, the vertical displacement is maximum, thus potential energy is maximum.
Kinetic energy at the lowest point = Potential energy at the highest point
From my explanation above, h is the vertical displacement, when potential energy of the pendulum is maximum. Considering a right angled triangle, this vertical displacement, h is the adjacent of the triangle, and it is equal to
L - Lcosθ.
h = 48.5 - 48.5cos(65.4) = 28.31 cm = 0.2831 m
Therefore, the speed of the mass upon reaching its lowest point is 2.36m/s