Mechanics | Relativity Answers

8. A water filled cone of height 50 cm and base area 20 sq cm is placed on a table with the base
on the table. What is the thrust offered by the water on the table?

6. A block of wood floats in freshwater with two-thirds of its volume submerged. In oil the block
floats with 0.90 of its volume submerged. Find the density of the wood and the oil.

7. An iron anchor of density 7870 kg/m3
appears 200 N lighter in water than in air. What is the
volume of the anchor? How much does it weigh in air?

14. Two clay balls are moving toward each other along a common straight line. The one on the
left has mass 3 kg and velocity 4 m/s. The one on the left has mass 2 kg and velocity 9 m/s. The
balls collide and form a single ball of mass 5 kg and keep moving. Some kinetic energy is lost as
heat in this process. Calculate this lost energy.

12. The speed of a motor boat with respect to water is v = 14 m/s. The speed of water with
respect to the banks is 6 m/s. When the boat began travelling upstream, a buoy was dropped from
it. A buoy is a body that can float in water. The boat travelled 6.3 km upstream (with respect to
banks), turned about and caught up with the buoy. Find the time T lapsed between dropping the
buoy and catching up with it again

Water is flowing continuously from a tap having an internal diameter 8 × 10–3 m. The water velocity as it leaves the tap is 0.4 ms–1.The diameter of the water stream at a distance 2 × 10–1 m below the tap is close to :-
(1) 9.6 × 10–3 m
(2) 3.6 × 10–3 m
(3) 5.0 × 10–3 m
(4) 7.5 × 10–3 m

THE LINE OF ACTION OF THE RESULTANT FORCE OF TWO LIKE PARALLEL FORCES SHIFTS BY ONE-FOURTH OF THE DISTANCE BETWEEN THE FORCES WHEN THE FORCES ARE INTERCHANGED. THE RATIO OF THE TWO FORCES IS ?

A stone is projected from a point on the ground so as to hit a bird on the top of a vertical pole of height h and then attain a max. height 2h above the ground . If at the instant of projection the bird flies away horizontally with a uniform speed and the stone hits the bird while descending , then ratio of speed of bird to the horizontal speed of the bird is ?

A NUMBER OF TUNING FORKS ARE ARRANGED IN ORDER OF INCREASING FREQUENCY AND ANY 2 SUCCESSIVE TUNING FORKS PRODUCE 4BEATS/S WHEN SOUNDED TOGETHER. IF THE LAST TUNING FORK HAS A FREQUENCY OCTAVE HIGHER THAN THE FIRST AND FREQUENCY OF THE FIRST IS 256 Hz. THEN THE NUMBER OF TUNING FORKS IS :
1. 63
2. 64
3. 65
4. 66

SOUND WAVES OF F=600Hz FALL NORMALLY ON A PERFECTLY REFLECTING WALL . THE SHORTEST DISTANCE AT WHICH ALL PARTICLES WILL HAVE MAX. AMPLITUDE OF VIBRATION IS :
1. 7/8m
2. 3/8m
3. 1/8m
4. 1/4m

TWO IDENTICAL STRAIGHT WIRES ARE STRETCHED SO AS TO PRODUCE 6 BEATS/S WHEN VIBRATING SIMULTANEOUSLY. ON CHANGING THE TENSION IN ONE OF THEM , BEAT FREQUENCY REMAINS SAME. DENOTING BY T1 AND T2 , THE HIGHER AND THE LOWER INITIAL TENSION IN THE STRING , THEN IT COULD BE SAID THAT WHILE MAKING THE ABOVE CHANGES IN THE TENSION :
1. T2 WAS DECREASED
2. T2 WAS INCREASED
3. T1 WAS INCREASED
4. NONE OF THE ABOVE