In an auditorium, a physics teacher uses a pendulum made by hanging a bowling ball from a wire to the ceiling. At the low point in its swing, a ball with a mass of 7.2-kg has a speed of 6 m/s. Ignoring air resistance, how high will the bob swing above the low point before reversing direction?

Question

In an auditorium, a physics teacher uses a pendulum made by hanging a bowling ball from a wire to the ceiling.  At the low point in its swing, a ball with a mass of 7.2-kg has a speed of 6 m/s.  Ignoring air resistance, how high will the bob swing above the low point before reversing direction?

My book and slides from professor do not address pendulums! How do  I start this?

bobpursley · Accepted Answer

The KE at the bottom is equal to the max PE at the top. 1/2 m v^2=mgh h= .5 (6^2)/9.8 meters

R_scott · Answer

the kinetic energy of the bob becomes gravitational potential energy 1/2 * m * v^2 = m * g * h

mssailormouth · Answer

1/2(7.2)(6^2)=7.2(9.8)h h=1.8