Athin rod of length 0.75 m and mass 0.42 kg is suspended freely from one end. it is pulled to one side and then allowed to swing like a pendulum, passing through its lowest position with an angular speed of 4.0 rad/s. neglecting friction and air resistance, find (a) the rod’s kinetic energy at its lowest position, (b) and how far above that position the center of mass rises.
the answer to one is the sun the answer to two is the last option
answer: 19.6 m
a rock is dropped from the cliff. it means its initial velocity, u = 0 m/s
it free falls under gravity.
using the second equation of motion:
s = u t + 0.5 a t²
s = height of cliff
u = initial velocity = 0
t = time of fall = 2.0 s
a = g = acceleration due to gravity = 9.8 m/s²
⇒ s = 0 + 0.5 × 9.8 m/s² × (2.0 s)² = 19.6 m