Page 1 :
(i) F, represents the upthrust 0, 9 mM stone due to w, water., , (ii) m, represents the mass of wate, ; ater displaced by, , iii) Net force acting on stone =, , é 1 Jade F, — F, (downwards), , (iv) Given : V= 80 cm’, p = 1 g cm? ,, 2, Gms cp Onan) secs, , m= 200 = =, , 1000, ., weight of stone F, = mg = 0-2 kg x 10 ms*=2N, , kg = 0-2 kg, , Mass of water displaced m, = Vp = 80 x 1 =80, aS, 80, , = Fp00 KE= 0-08 ke, , upthrust F, = 1,8 = 0-08 kg x 10 ms? =0-8N, Hence net downward force on stone, , = dW,, , Force, , , , , , -, Acceleration =, Mass, , Given : Volume of iron piece = 100 cm?, — 100 x 10° m’ = 104 m?, (i) Weight of iron piece in air, = Volume *, =104 x (78% 10°, (i) Upthrust = (Volume of water displaced), of water X &, , But volume of water disp!, piece when it is completely immers, Upthrust = 10-4 x 1000 x, , (iii) Apparent weight = True weight —, ag eS, , density of iron x &, ) x 10 = 7:3 .N, , x density, , Upthrust, , , , , , , , n and density 7-9 g, hread and is, , Sit}, , cm ~, , , , immersed, , , , , , the upthrust, , , , (a) Given, side of cube = 5 cm, “. Volume of the cube = 5 x5 x 5 = 125 cm’, Mass of the cube = Volume x density, = 125 em? x 7-9 g cnr?, = 987-5 g, .. Weight of the cube = 987:5 ef (downwards), (b) Upthrust on cube= Weight of liquid displaced, = Volume of cube x density of liquid x g, = 15 xItxXg =Biset (upwards), (c) Tension in thread = Net downward force, = Weight of cube — Upthrust on cube, = 987-5 — 137-5 = 850-0 gf., , show that it, , Given, weight of solid =W, :. Mass of solid = W/g, , , , Ww, Volume of solid = Mass_ _ Wiss, Density p, Volume of liquid displaced = Volume of solid, pig, , Pp, Upthrust on solid = Volume of liquid displaced, x density of liquid, x acceleration due to gravity, , W/g W, or upthrust = Oe eee P,, Pp pP, ;. Apparent weight = True weight — upthrust, , no [54 pola), , Hence proved., , , , , Sus, , force needed to keep 4 block of wood inside, , f, Ue, , term UP ter ?, What do you understand Oy its existe” | Ans. Upthrust due to water on block when, en » . °, 2 ‘recti oH d at what point does the buoyant fully submerged is more than its weight., anne el liquid, act ? | 4 A piece of wood if left under water, comes to the, force on a bey ee t the centre of puoyancy: | surface. Explain the reason., Ans wards, @ A g, Describe an experiment to show that a body immersed in, 3. What is meant by the term buoy e a liquid appears lighter than it ay iS. Pei k, its S-Lt™ body weigh more in air or in vacuum when We, Be caine upthrns’ ana st 7 At ich point on ae abe ieee 9 Give a reason for your answer., 5. What i of upthms® ” | aamguadie, : at is the cause :, j 109, , be considered t© act *