A 0.80-kg object tied to the end of a 2.0-m string swings as a pendulum.At the lowest point of its swing,the object has a kinetic energy of 10 J.Determine the speed of the object at the instant when the string makes an angle of 50$\degree$with the vertical.
A)5.6 m/s
B)4.4 m/s
C)3.3 m/s
D)5.0 m/s
E)6.1 m/s

Question

Quizplus · Accepted Answer

The kinetic energy at the lowest point is 10 J, which gives a speed of 5 m/s. At 50 degrees, some energy is potential, so use energy conservation: KE + PE = 10 J. Calculate the height change using trigonometry, then solve for the new speed.

A 080-Kg Object Tied to the End of a 2 °\degree°

A 080-Kg Object Tied to the End of a 2 $\degree$