DrBESTJC:



Volume of the hydrometer when floating in water,V1 = Volume of the weighted bulb + Volume of the cylindrical stem.....
Volume of the wighted bulb = 30cm^3.
Volume of the cylindrical stem = §(pie) * r^2(radius squared) * L1.
.: V1 = 30cm^3 + §r^2h1.
But Cross-sectional area of the cylinder = §r^2 = 1cm^2 (given in the question).
Length of the stem immersed when the hydrometer is floating in water,L1 = 3cm.
.: volume of the hydrometer when floating in water,V1 = 30cm^3 + (1cm^2 * 3cm) = 30cm^3 + 3cm^3 = 33cm^3.

Secondly,

Volume of the hydrometer when floating in the Liquid,V2 = Volume of the weighted bulb + volume of the cylindrical stem....
Volume of the weighted bulb = 30cm^3 ........... and
Volume of the cylindrical stem = §(pie) * r^2(r squared) * L2
.: V2 = 30cm^3 + §r^2L2.
But, cross-sectional area of the cylinder = §r^2 = 1cm^2....

DrBESTJC:
HOT CHEMISTRY.

Hydrogen Sulphide is prepared at one end of a laboratory. It takes 5 seconds for a student at the other end to smell it. How long will it take to smell sulphur dioxide from the same position?
(A) 5 seconds also.
(B) 2.5 seconds.
(C) 3.6 seconds.
(D) 9.4 seconds.
(E) 2.7 seconds.

Please SHOW FULL WORKINGS!

Eben331:
(1) A swimmer is capable of swimming at 1.4m/s in still water. (a) how far downstream will be land if he swims directly across a 180m wide river? (b) how long will it take him to reach the other side? (2) A man can row at 6km/hr in still water and wants to cross a river to a position exactly opposite his starting point. If the river is 5km wide and is flowing at 4km/hr eastwards, find the direction in which he must set off in order to accomplish his objective. How long will it take to cross the river?

centitan:

Sent,Check your mail.

Aceed:
What is the tension in the cable holding
a mine of mass 600kg and volume 0.8m^3 to
the sea bed, so that it is totally submerged.

OyedejiIfedayo:
Pls my brother aspiring for MBBS had a very high score in UTME and wrote this years WAEC. But on checking his waec result it displayed no result for this candidate.
I was unhappy when he told me he hasn't seen his result till the present moment even though he has made complaint.
Pls can anyone advise on what can still be done.

simplebb:

That's serious. Did he write NECo exam this year? BTW the problem, was it a centre issue or only him?

Aceed:


A block of material of volume 20cm^3 and
density 2.5gcm^-3 is suspended from a spring
balance with half the volume of the block
immersed in water. What is the reading of the
spring balance? (density of water = 1.0gcm^-3)

Aceed:


What volume of alcohol with a density of
8.4 x 10^2 kgm^-3 will have the same mass as
4.2m^3 of petrol whose density is 7.2 x 10^2 kgm^-3?

Aceed:


A force of 300N was used to pull a load of
mass 40kg at a steady speed up an inclined
of length 6.2m and vertical height 3.5m.
Determine the velocity ratio

Aceed:


A body of mass 700g hangs from the end of a
long wire fixed to a high tree. A horizontal
string attached to the body pulls it until the
wire is at 30 degrees to the vertical. Find
the tensions in both the string and the wire.

Aceed:
DrBESTJC...OGA NA MASTER... ...hmmm which course you dey vie for... you don scatter book oooo

DrBESTJC:



From Density = Mass/volume
.: Mass = Density * volume = 2.5g/cm^3 * 20cm^3 = 50g = (50/1000)Kg = 0.05Kg.
Weight of the block in air = mg = 0.05Kg * 10m/s2 = 0.5N.

Now,

Half of the volume of the block is immersed in water; which implies: 1/2 * 20cm^3 = 10cm^3.
Upthrust = density * volume * g(acceleration due to gravity) = 1g/cm^3 * 10cm^3 * g = 10g * g = (10/1000)Kg * 10m/s^2 = 0.01Kg * 10m/s^2 = 0.1N

Reading of the spring balance = Tension in the spring of balance = Weight of the block in air - Upthrust = 0.5N -0.1N = 0.4N

Nltaliban:



If you ask me, you stand a good chance in Ui but it's up to you to take the risk.


Think we'll, it's your decision. There's every probably that the time that will be given to you to accept Oou's admission would have elapsed before Ui will conduct postume.


Think well, if you think you're ready to take the challenge and Prove yourself as a champion.

Aceed:


answer to this was 40g

OyedejiIfedayo:


He didn't write NECO.
it was centre problem.

iremide12:
pls I don't grab your that second paragraph/statement

DrBESTJC:


I think it is wrong because tension is a force whose unit is Newton.


But you can still convert the value in Newton to gramms...thus
F = mg ...where m = F/g = 0.4/10 = 0.04Kg.
Then,multiply by 1000 to convert to gramms = 0.04 * 1000 = 40g

Nltaliban:



Are you in whatsapp so I send a voice note?

I really can't type much