Other Physics Answers

Specific heat capacity of water

 Derive the formula for the moment of inertia of a uniform sphere of radius r0 and mass M about an axis through its center.[Hint: Divide thesphere into infinitesimally thin disks of thickness of dy and integrate over these cylindrical disks.]

The reaction time is the time intervel in which a person

To study for your upcoming assignment, you have placed two of your favorite physics textbooks, one on top of another, on your table as shown. The mass of book 1 is 600 grams. The mass of book 2 is 300 grams. The coefficient of kinetic friction between book 1 and the table is μ

k(g,1)

=0.2

. The coefficient of static friction between book 1 and book 2 is μ

s(1,2)

=0.3

. Use g=9.81m/s

2

Find, in Newtons, F

max

, the maximum force with with you can push the book at the bottom (book 1) such that both books slide together on the table, without the book on the top (book 2) sliding off

Choose any THREE time periods. In each time period write a paragraph of ten lines based

on your understanding of the differences of the time periods. Locate the time period in your

own context. (15)

 The diameter of a deoxyribonucleic acid (DNA) molecule is about 20 angstroms. Express the surface area of the molecule in a square meters and square inches. 

The moon has mass M 7.7 10²² kg and radius r 1.7 10⁶ m. Calculate work done needed to launch a 1500 kg spacecraft from its surface to other surface.

(i) By giving an explanation, state whether frictional force is a conservative or

non-conservative force.

(ii) When the three blocks in Fig. 2 are released from rest, they accelerate with a

magnitude of 0.500 m/s2. Block 1 has mass M, block 2 has 2M, and block 3 has

2M. Determine the coefficient of kinetic friction between block 2 and the table.

[3,6]

A rectangular block of low density material weighs 25.0 N. A thin string is attached to the center

of the horizontal bottom of the block and tied to the bottom of a beaker partially filled with water.

When 20% of the block’s volume is submerged, the tension in the string is 15.0 N.

(i) Calculate the buoyant force acting on the block.(ii) The string breaks when the tension reaches 65 N, and at this moment, 25%

of the block’s volume is still below the water line. Determine the fraction

of the block’s volume that is below the top surface of the oil.

[3,5]

a pool contains of 2500³ of water with a density of 1000kg/m³ at 10°C , the pool is heated to 20°C and expands by 5.25m³ , calculate the density