The bob of mass 50 gm of a pendulum is released from a horizontal position A as shown in the figure . .If the length of the pendulum is `1.5` m , what is its kinetic energy at the lower most point B ? `(g = 10 m/(s^(2)))`

Options

A. `2.5 xx10^(-11)` J
B. `15 xx10^(-1) J `
C. `5xx10^(-1) J `
D. `7.5 xx10^(-1) J `

Answer

D

Explanation

Potential energy of a bob of pendulum at point A = K.E of bob at point B
` :. ` K.E of bob at `B(1/2 mv^(2)) = mgh `
` = 50 xx10^(-3) xx10 xx1/5`
`= 7.5 xx10^(-1) J `