Potential energy of an object with mass of 966 kg and height of 72 m

Just to estimate an answer (which you should always do in physics)

Givens

g = 9.81 (call it 10 for estimation purposes)

m = 966 (call it 1000 for estimation purposes)

h = 72 m

Ep = m*g * h

Ep = 1000 * 10 * 72

Ep = 720000 So this is about what you should get.

Exact answer

Ep = 9.81 * 966 * 72

Ep = 682305 which should be rounded to 2 places.

Ep = 6.8 * 10 ^5

d

explanation:

v=uf/(u-f)

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

=50/-5

=-10 cm (formed at other side)