1 Answers

A piece of substance of specific heat capacity 450Jkg⁻¹k⁻¹ falls…

Posted by: 303 views ,
PHYSICS

A piece of substance of specific heat capacity 450Jkg⁻¹k⁻¹ falls through a vertical distance of 20m from rest. Calculate the rise in temperature of the substance on hitting the ground when all its energies are converted into heat. [g = 10ms⁻²]

A. 2/9⁰C

B. 4/9⁰C

C. 9/2⁰C

D. 9/4⁰C

QUICK ANSWER…

B

DETAILS…

If a piece of substance of specific heat capacity 450Jkg⁻¹k⁻¹ falls through a vertical distance of 20m from rest, the rise in temperature of the substance on hitting the ground when all its energies are converted into heat will be calculated as 4/9⁰C, let me explain…

The potential energy of the substance = mgh

RELATED!  Heat is supplied uniformly at the rate of 100W to 1.0 × 10¯²kg of a...

The heat energy of the same substance = mcΔT

Where;

m = mass of the substance,

g = acceleration due to gravity,

h = height of substance location from the ground,

c = specific heat capacity of the substance, and

ΔT = change in temperature.

If all the potential energy of the substance is converted to heat, we have:

mgh = mcΔT

mgh = mcΔT

gh = cΔT

therefore,

ΔT = gh/c

ΔT = (10 × 20)/450

ΔT = 200/450

ΔT = 4/9K = 4/9⁰C

Now for the right answer to the above question:

  1. Option A is incorrect.
  2. Option B is incorrect.
  3. C is incorrect.
  4. D is the correct answer.

KEY-POINTS…

You may please note these/this:

  • Even though this cannot happen in real life, the assumption that all the potential energy got converted into heat is a mere theoretical exercise.

If you love our answers, you can simply join our community and also provide answers like this, fellow learners like you will appreciate it.

/ culled from 2021 JAMB-UTME PHYSICS question 29 /

1 Answers

  1. 0 Votes Thumb up 0 Votes Thumb down 0 Votes

    Please note that if the change in temperature is a given value in degree Celsius, the change measured in kelvin will also be the same value.

    Admin - Mar 25, 2022 | Reply


Answer Question