A tube with sealed ends has some sand at one end. When the tube is turned upside down the sand falls 0.6m then settles down again. The energy stays in the sand as thermal energy. Use g=9.81m/s2. 1) If the mass of the sand is 0.5kg, how much thermal energy is added on each turn? Increase of U=

2.943 J

Explanation:

Data:

acceleration due to gravity, g = 9.81 m/s²

mass of sand  = 0.5 kg

distance  = 0.6

Thermal energy  = the energy possessed by the falling sand

The force of sand = ma

                              =

However, the energy is given as the force multiplied by the distance, so

E =fd

Therefore, the thermal energy is 2.943 joules

The thermal energy added would be 2.94 J

Explanation:

Part 1

The increase in thermal energy is equal to the new potential energy of the body. As the sand falls and stop at 0.6 m it gains thermal energy in form of the potential energy;

Given the mass = 5 kg

g acceleration due to gravity = 9.8 m/

increase in U would be  

+U = mgh

       = 0.5 x 0.6 x 9.8

      = 2.94 J

Therefore 2.94 J is added to the thermal energy of the body.

8 meters above the spring

d

explanation:

v=uf/(u-f)

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

=50/-5

=-10 cm (formed at other side)