A stone of mass 250 g is located at a height of 20 m calculate the potential energy of the stone?

50J

Explanation:

Potential energy = mass (kg) * gravitational accelerations (10N on earth) * height

250 g in kg = 0.25

0.25 * 10 * 20 = 50 J

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.