# Physics

posted by .

A 0.28-kg stone is held 1.5 m above the top edge of a water well and then dropped into it. The well has a depth of 4.8 m.
(a) Taking y = 0 at the top edge of the well, what is the gravitational potential energy of the stone–Earth system before the stone is released?
J

(b) Taking y = 0 at the top edge of the well, what is the gravitational potential energy of the stone–Earth system when it reaches the bottom of the well?
J

(c) What is the change in gravitational potential energy of the system from release to reaching the bottom of the well?
J

• Physics -

a. PE = mgh = 0.28 * 9.8 *1.5 = 4.1J.

b. PE = 0.28 * 9.8 * 4.8 = 13.2 Joules.

c. Change = mg(h1+h2) - 0 =
0.28 * 9.8 * (1.5+4.8) - 0 = 17.3J.

• Physics -

Actually,

** GPE = mgh

a) GPE = mgh
as height of well is taken to be area of 0 GPE.
sign is positive.
GPE = mgh = 0.28*9.8*1.5

b) GPE = mgh
as height is now below area of 0 GPE, h changes to -h.
therefore sign is negative
GPE = 0.28*9.8*(-4.8)

c) GPE = mgh
here, mg(-h1-h2)
therefore,
GPE = 0.28*9.8*(-1.5-4.8)

## Similar Questions

1. ### physics

A person standing at the edge of a seaside cliff kicks a stone over the edge with a speed of vi = 11 m/s. The cliff is h = 55 m above the water's surface, as shown below. How long does it take for the stone to fall to the water?
2. ### physics

9. A stone is thrown at an angle of 30° above the horizontal from the top edge of a cliff with an initial speed of 19.6 m/s. A stop watch measures the stone's trajectory time from top of cliff to bottom to be 6.7 s. How far out from …
3. ### physics

A person standing at the edge of a seaside cliff kicks a stone over the edge with a speed of vi = 13 m/s. The cliff is h = 58 m above the water's surface, as shown below. (a) How long does it take for the stone to fall to the water?
4. ### Physics

A 0.31-kg stone is held 1.2 m above the top edge of a water well and then dropped into it. The well has a depth of 5.6 m. (a) Taking y = 0 at the top edge of the well, what is the gravitational potential energy of the stone–Earth …
5. ### physics

A person standing at the edge of a seaside cliff kicks a stone over the edge with a speed of vi = 16 m/s. The cliff is h = 60 m above the water's surface, as shown below. (a) How long does it take for the stone to fall to the water?
6. ### physics

A person standing at the edge of a seaside cliff kicks a stone over the edge with a speed of vi = 16 m/s. The cliff is h = 60 m above the water's surface, as shown below. How long does it take for the stone to fall to the water?
7. ### Physics

a person standing at the edge of a seaside cliff kicks a stone over the edge with a speed of 10 m/s. the cliff is 48 m above the water's surface as shown. how long does it take for the stone to fall to the water?
8. ### Physics

a person standing at the edge of a seaside cliff kicks a stone horizontally over the edge with speed of 31 m/s cliff is 51 m above water. how far from base of cliff does stone land and what is speed of stone when it hits water
9. ### Physics

a stone is thrown at an angle of 30 degrees above the horizontal from the top edge of a cliff with an initial speed of 12m/s. a stop watch measures the stone's trajectory time from top of cliff to bottom to be 8s. how far out from …
10. ### physics

A stone is dropped from edge of a roof and is observed to pass a window, vertically below it. The stone takes 0.1 sec to fall between the top and bottom of the window. If the window is of 2 m height, how far is the roof above the top …

More Similar Questions