Josh did an experiment recording the changes in temperature in sand and water when exposed to a light source, and then when the light source was removed. josh noticed that the sand heated up faster than the water and then cools faster than the water. josh concludes that

a) sand is the better insulator.

b) water is the better conductor.

c) water is the better insulator.

d) sand has a higher heat capacity.

Option (C) is the correct answer.

Explanation:

Heat capacity is defined as the heat amount required to raise one degree temperature of a system.

Heat capacity of water is 4.184 J and heat capacity of sand is 0.290 J. So, less is the value of heat capacity of a substance more is the amount of heat absorbed by it.

Whereas substances which are able to conduct heat and electricity efficiently are known as conductors. The substances which are not able to efficiently conduct heat and electricity are known as insulators.

Therefore, water is a better insulator as compared to sand as it does not heat readily.

Thus, Josh concludes that water is the better insulator, is true.

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j

it is a solid

explanation: