Home » Posts tagged 'England'

Tag Archives: England

Buoyancy

A pound coin floating in mercury (Photo credit: Wikipedia)

I read in one of my chapters that when a body is immersed in a container of water (kept on a weighing machine which  reads ‘W’ at first )the apparent weight lost by the body is equal to the buoyant force, and thus the reading ‘W’ increases.

Then I came across a question like this –

A beaker containing water kept on a weighing machine weighs W. A body of weight  ‘w’ is dropped in it. It is floating & experiencing a buoyant force B, then the reading on machine is –

(a)w+W
(b)W+B
(C)W+w-B
(d)W

please give me the answer and explanation
the book says answer is (a)
but I think it is (c)

(Anwesha posted this questions)

The answer is A.

The total force acting downwards is W+w and the weighing scale is providing an equal reaction. the normal reaction offered by the weighing scale is what we get as the reading.

therefore the reading on the weighing scale must be W+w

The buoyant force is acting on the object dropped and is not contributing to the normal reaction offered by the weighing scale.

Relative motion – Problem

A driving instructor tells his student to maintain a 3 second separation between the students car and the car ahead.

English: At The King Street Roundabout Traffic...

Suppose the cars are traveling 25m/s. How many meters apart are the cars? If the trailing car brakes at 9m/s^2 how much distance is required to stop?

(Received via SMS from the Mobile site of askphysics )

Get more such problems here and here

Answer:

a) 75 m

b)

Physics Numerical Problem

A small mass of 10 KG is suspended from a spring balance. It is Pulled by Horizontal Spring so it makes 60º with the vertical. Find the new reading of the spring balance.

%d bloggers like this: