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Question Number 20412 Answers: 0 Comments: 3

A block is placed on a rough horizontal surface. The minimum force required to slide the block is

$$\mathrm{A}\:\mathrm{block}\:\mathrm{is}\:\mathrm{placed}\:\mathrm{on}\:\mathrm{a}\:\mathrm{rough}\:\mathrm{horizontal} \\ $$$$\mathrm{surface}.\:\mathrm{The}\:\mathrm{minimum}\:\mathrm{force}\:\mathrm{required} \\ $$$$\mathrm{to}\:\mathrm{slide}\:\mathrm{the}\:\mathrm{block}\:\mathrm{is} \\ $$

Question Number 20411 Answers: 1 Comments: 0

A stone of weight W is thrown straight up from the ground with an initial speed u. if a drag force of constant magnitude f acts on the stone through out its flight, the speed of stone just before reaching the ground is

$$\mathrm{A}\:\mathrm{stone}\:\mathrm{of}\:\mathrm{weight}\:{W}\:\mathrm{is}\:\mathrm{thrown}\:\mathrm{straight} \\ $$$$\mathrm{up}\:\mathrm{from}\:\mathrm{the}\:\mathrm{ground}\:\mathrm{with}\:\mathrm{an}\:\mathrm{initial} \\ $$$$\mathrm{speed}\:{u}.\:\mathrm{if}\:\mathrm{a}\:\mathrm{drag}\:\mathrm{force}\:\mathrm{of}\:\mathrm{constant} \\ $$$$\mathrm{magnitude}\:{f}\:\mathrm{acts}\:\mathrm{on}\:\mathrm{the}\:\mathrm{stone}\:\mathrm{through} \\ $$$$\mathrm{out}\:\mathrm{its}\:\mathrm{flight},\:\mathrm{the}\:\mathrm{speed}\:\mathrm{of}\:\mathrm{stone}\:\mathrm{just} \\ $$$$\mathrm{before}\:\mathrm{reaching}\:\mathrm{the}\:\mathrm{ground}\:\mathrm{is} \\ $$

Question Number 20409 Answers: 1 Comments: 1

Calculate the force (F) required to cause the block of mass m_1 = 20 kg just to slide under the block of mass m_2 = 10 kg [coefficient of friction μ = 0.25 for all surfaces]

$${Calculate}\:{the}\:{force}\:\left({F}\right)\:{required}\:{to} \\ $$$${cause}\:{the}\:{block}\:{of}\:{mass}\:{m}_{\mathrm{1}} \:=\:\mathrm{20}\:{kg} \\ $$$${just}\:{to}\:{slide}\:{under}\:{the}\:{block}\:{of}\:{mass} \\ $$$${m}_{\mathrm{2}} \:=\:\mathrm{10}\:{kg}\:\left[{coefficient}\:{of}\:{friction}\:\mu\right. \\ $$$$\left.=\:\mathrm{0}.\mathrm{25}\:{for}\:{all}\:{surfaces}\right] \\ $$

Question Number 20375 Answers: 1 Comments: 1

A small particle of mass m is projected at an angle θ with the x-axis with an initial velocity v_0 in the x-y plane as shown in the Figure. At a time t < ((v_0 sin θ)/g), the angular momentum of the particle is

$$\mathrm{A}\:\mathrm{small}\:\mathrm{particle}\:\mathrm{of}\:\mathrm{mass}\:{m}\:\mathrm{is}\:\mathrm{projected} \\ $$$$\mathrm{at}\:\mathrm{an}\:\mathrm{angle}\:\theta\:\mathrm{with}\:\mathrm{the}\:{x}-\mathrm{axis}\:\mathrm{with}\:\mathrm{an} \\ $$$$\mathrm{initial}\:\mathrm{velocity}\:{v}_{\mathrm{0}} \:\mathrm{in}\:\mathrm{the}\:{x}-{y}\:\mathrm{plane}\:\mathrm{as} \\ $$$$\mathrm{shown}\:\mathrm{in}\:\mathrm{the}\:\mathrm{Figure}.\:\mathrm{At}\:\mathrm{a}\:\mathrm{time} \\ $$$${t}\:<\:\frac{{v}_{\mathrm{0}} \:\mathrm{sin}\:\theta}{{g}},\:\mathrm{the}\:\mathrm{angular}\:\mathrm{momentum}\:\mathrm{of} \\ $$$$\mathrm{the}\:\mathrm{particle}\:\mathrm{is} \\ $$

Question Number 20578 Answers: 0 Comments: 2

Tinkutara and Ajfour please how do you do the following using lekh diagram: (i)introduction of dotted lines (ii)writing of letters (iii)shading (iv)putting colours in a diagram (v)draw live figures like birds thanks for the help

$$\:{Tinkutara}\:{and}\:\:{Ajfour}\:{please}\:{how} \\ $$$${do}\:{you}\:{do}\:{the}\:{following}\:{using} \\ $$$${lekh}\:{diagram}: \\ $$$$\left({i}\right){introduction}\:{of}\:{dotted}\:{lines} \\ $$$$\left({ii}\right){writing}\:{of}\:{letters} \\ $$$$\left({iii}\right){shading} \\ $$$$\left({iv}\right){putting}\:{colours}\:{in}\:{a}\:{diagram} \\ $$$$\left({v}\right){draw}\:{live}\:{figures}\:{like}\:{birds} \\ $$$$ \\ $$$${thanks}\:{for}\:{the}\:{help} \\ $$

Question Number 20349 Answers: 0 Comments: 3

A ball rolled on ice with a velocity of 14 ms^(−1) comes to rest after travelling 40 m. Find the coefficient of friction. (Given, g = 9.8 m/s^2 )

$$\mathrm{A}\:\mathrm{ball}\:\mathrm{rolled}\:\mathrm{on}\:\mathrm{ice}\:\mathrm{with}\:\mathrm{a}\:\mathrm{velocity}\:\mathrm{of} \\ $$$$\mathrm{14}\:\mathrm{ms}^{−\mathrm{1}} \:\mathrm{comes}\:\mathrm{to}\:\mathrm{rest}\:\mathrm{after}\:\mathrm{travelling} \\ $$$$\mathrm{40}\:\mathrm{m}.\:\mathrm{Find}\:\mathrm{the}\:\mathrm{coefficient}\:\mathrm{of}\:\mathrm{friction}. \\ $$$$\left(\mathrm{Given},\:{g}\:=\:\mathrm{9}.\mathrm{8}\:\mathrm{m}/\mathrm{s}^{\mathrm{2}} \right) \\ $$

Question Number 20346 Answers: 0 Comments: 3

To paint the side of a building, painter normally hoists himself up by pulling on the rope A as in figure. The painter and platform together weigh 200 N. The rope B can withstand 300 N. Find the maximum acceleration of the painter.

$$\mathrm{To}\:\mathrm{paint}\:\mathrm{the}\:\mathrm{side}\:\mathrm{of}\:\mathrm{a}\:\mathrm{building},\:\mathrm{painter} \\ $$$$\mathrm{normally}\:\mathrm{hoists}\:\mathrm{himself}\:\mathrm{up}\:\mathrm{by}\:\mathrm{pulling}\:\mathrm{on} \\ $$$$\mathrm{the}\:\mathrm{rope}\:{A}\:\mathrm{as}\:\mathrm{in}\:\mathrm{figure}.\:\mathrm{The}\:\mathrm{painter}\:\mathrm{and} \\ $$$$\mathrm{platform}\:\mathrm{together}\:\mathrm{weigh}\:\mathrm{200}\:\mathrm{N}.\:\mathrm{The} \\ $$$$\mathrm{rope}\:{B}\:\mathrm{can}\:\mathrm{withstand}\:\mathrm{300}\:\mathrm{N}.\:\mathrm{Find}\:\mathrm{the} \\ $$$$\mathrm{maximum}\:\mathrm{acceleration}\:\mathrm{of}\:\mathrm{the}\:\mathrm{painter}. \\ $$

Question Number 20344 Answers: 1 Comments: 3

Determine the speed with which block B rises in figure if the end of the cord at A is pulled down with a speed of 2 m/s.

$$\mathrm{Determine}\:\mathrm{the}\:\mathrm{speed}\:\mathrm{with}\:\mathrm{which}\:\mathrm{block} \\ $$$${B}\:\mathrm{rises}\:\mathrm{in}\:\mathrm{figure}\:\mathrm{if}\:\mathrm{the}\:\mathrm{end}\:\mathrm{of}\:\mathrm{the}\:\mathrm{cord}\:\mathrm{at} \\ $$$${A}\:\mathrm{is}\:\mathrm{pulled}\:\mathrm{down}\:\mathrm{with}\:\mathrm{a}\:\mathrm{speed}\:\mathrm{of}\:\mathrm{2}\:\mathrm{m}/\mathrm{s}. \\ $$

Question Number 20338 Answers: 0 Comments: 0

Why Al_2 O_3 is amphoteric while B_2 O_3 is acidic?

$$\mathrm{Why}\:\mathrm{Al}_{\mathrm{2}} \mathrm{O}_{\mathrm{3}} \:\mathrm{is}\:\mathrm{amphoteric}\:\mathrm{while}\:\mathrm{B}_{\mathrm{2}} \mathrm{O}_{\mathrm{3}} \\ $$$$\mathrm{is}\:\mathrm{acidic}? \\ $$

Question Number 20337 Answers: 0 Comments: 0

Why oxidising character of F_2 > Cl_2 ?

$$\mathrm{Why}\:\mathrm{oxidising}\:\mathrm{character}\:\mathrm{of}\:\mathrm{F}_{\mathrm{2}} \:>\:\mathrm{Cl}_{\mathrm{2}} ? \\ $$

Question Number 20335 Answers: 0 Comments: 0

Covalent radius of an element having 82 electrons in extranuclear part and 82 protons in the nucleus is 146 A^o . Calculate the electronegativity on Allred Rochow scale of that element.

$$\mathrm{Covalent}\:\mathrm{radius}\:\mathrm{of}\:\mathrm{an}\:\mathrm{element}\:\mathrm{having} \\ $$$$\mathrm{82}\:\mathrm{electrons}\:\mathrm{in}\:\mathrm{extranuclear}\:\mathrm{part}\:\mathrm{and}\:\mathrm{82} \\ $$$$\mathrm{protons}\:\mathrm{in}\:\mathrm{the}\:\mathrm{nucleus}\:\mathrm{is}\:\mathrm{146}\:\overset{\mathrm{o}} {\mathrm{A}}.\:\mathrm{Calculate} \\ $$$$\mathrm{the}\:\mathrm{electronegativity}\:\mathrm{on}\:\mathrm{Allred}\:\mathrm{Rochow} \\ $$$$\mathrm{scale}\:\mathrm{of}\:\mathrm{that}\:\mathrm{element}. \\ $$

Question Number 20334 Answers: 0 Comments: 0

Choose the correct regarding E.N. (1) B > Al > Ga > In (2) B > Al = Ga = In (3) B > In > Ga = Al (4) B > In > Ga > Al

$$\mathrm{Choose}\:\mathrm{the}\:\mathrm{correct}\:\mathrm{regarding}\:\mathrm{E}.\mathrm{N}. \\ $$$$\left(\mathrm{1}\right)\:\mathrm{B}\:>\:\mathrm{Al}\:>\:\mathrm{Ga}\:>\:\mathrm{In} \\ $$$$\left(\mathrm{2}\right)\:\mathrm{B}\:>\:\mathrm{Al}\:=\:\mathrm{Ga}\:=\:\mathrm{In} \\ $$$$\left(\mathrm{3}\right)\:\mathrm{B}\:>\:\mathrm{In}\:>\:\mathrm{Ga}\:=\:\mathrm{Al} \\ $$$$\left(\mathrm{4}\right)\:\mathrm{B}\:>\:\mathrm{In}\:>\:\mathrm{Ga}\:>\:\mathrm{Al} \\ $$

Question Number 20316 Answers: 0 Comments: 8

If at a height of 40 m, the direction of motion of a projectile makes an angle π/4 with the horizontal, then its initial velocity and angle of projection are, respectively (a) 30, (1/2)cos^(−1) (−(4/5)) (b) 30, (1/2)cos^(−1) (−(1/2)) (c) 50, (1/2)cos^(−1) (−(8/(25))) (d) 60, (1/2)cos^(−1) (−(1/4))

$$\mathrm{If}\:\mathrm{at}\:\mathrm{a}\:\mathrm{height}\:\mathrm{of}\:\mathrm{40}\:\mathrm{m},\:\mathrm{the}\:\mathrm{direction}\:\mathrm{of} \\ $$$$\mathrm{motion}\:\mathrm{of}\:\mathrm{a}\:\mathrm{projectile}\:\mathrm{makes}\:\mathrm{an}\:\mathrm{angle} \\ $$$$\pi/\mathrm{4}\:\mathrm{with}\:\mathrm{the}\:\mathrm{horizontal},\:\mathrm{then}\:\mathrm{its}\:\mathrm{initial} \\ $$$$\mathrm{velocity}\:\mathrm{and}\:\mathrm{angle}\:\mathrm{of}\:\mathrm{projection}\:\mathrm{are}, \\ $$$$\mathrm{respectively} \\ $$$$\left({a}\right)\:\mathrm{30},\:\frac{\mathrm{1}}{\mathrm{2}}\mathrm{cos}^{−\mathrm{1}} \left(−\frac{\mathrm{4}}{\mathrm{5}}\right) \\ $$$$\left({b}\right)\:\mathrm{30},\:\frac{\mathrm{1}}{\mathrm{2}}\mathrm{cos}^{−\mathrm{1}} \left(−\frac{\mathrm{1}}{\mathrm{2}}\right) \\ $$$$\left({c}\right)\:\mathrm{50},\:\frac{\mathrm{1}}{\mathrm{2}}\mathrm{cos}^{−\mathrm{1}} \left(−\frac{\mathrm{8}}{\mathrm{25}}\right) \\ $$$$\left({d}\right)\:\mathrm{60},\:\frac{\mathrm{1}}{\mathrm{2}}\mathrm{cos}^{−\mathrm{1}} \left(−\frac{\mathrm{1}}{\mathrm{4}}\right) \\ $$

Question Number 20200 Answers: 1 Comments: 0

Question Number 20182 Answers: 0 Comments: 0

Question Number 20177 Answers: 0 Comments: 0

But ans is (1/(108))

$${But}\:{ans}\:{is}\:\frac{\mathrm{1}}{\mathrm{108}} \\ $$

Question Number 20174 Answers: 2 Comments: 0

(0.1^− )^2 {1−9(0.16^− )^2 }

$$\left(\mathrm{0}.\overset{−} {\mathrm{1}}\right)^{\mathrm{2}} \left\{\mathrm{1}−\mathrm{9}\left(\mathrm{0}.\mathrm{1}\overset{−} {\mathrm{6}}\right)^{\mathrm{2}} \right\} \\ $$

Question Number 20058 Answers: 1 Comments: 0

What is the difference between ∮ and ∫? Where is ∮ used?

$$\mathrm{What}\:\mathrm{is}\:\mathrm{the}\:\mathrm{difference}\:\mathrm{between}\:\oint\:\mathrm{and} \\ $$$$\int?\:\mathrm{Where}\:\mathrm{is}\:\oint\:\mathrm{used}? \\ $$

Question Number 20042 Answers: 0 Comments: 3

In the situation given, all surfaces are frictionless, pulley is ideal and string is light, F = ((mg)/2) , find the acceleration of block 2.

$$\mathrm{In}\:\mathrm{the}\:\mathrm{situation}\:\mathrm{given},\:\mathrm{all}\:\mathrm{surfaces}\:\mathrm{are} \\ $$$$\mathrm{frictionless},\:\mathrm{pulley}\:\mathrm{is}\:\mathrm{ideal}\:\mathrm{and}\:\mathrm{string}\:\mathrm{is} \\ $$$$\mathrm{light},\:{F}\:=\:\frac{{mg}}{\mathrm{2}}\:,\:\mathrm{find}\:\mathrm{the}\:\mathrm{acceleration}\:\mathrm{of} \\ $$$$\mathrm{block}\:\mathrm{2}. \\ $$

Question Number 20040 Answers: 0 Comments: 3

The system shown in figure is given an acceleration ′a′ toward left. Assuming all the surfaces to be frictionless, find the force on the sphere by inclined surface.

$$\mathrm{The}\:\mathrm{system}\:\mathrm{shown}\:\mathrm{in}\:\mathrm{figure}\:\mathrm{is}\:\mathrm{given}\:\mathrm{an} \\ $$$$\mathrm{acceleration}\:'{a}'\:\mathrm{toward}\:\mathrm{left}.\:\mathrm{Assuming} \\ $$$$\mathrm{all}\:\mathrm{the}\:\mathrm{surfaces}\:\mathrm{to}\:\mathrm{be}\:\mathrm{frictionless},\:\mathrm{find} \\ $$$$\mathrm{the}\:\mathrm{force}\:\mathrm{on}\:\mathrm{the}\:\mathrm{sphere}\:\mathrm{by}\:\mathrm{inclined} \\ $$$$\mathrm{surface}. \\ $$

Question Number 20038 Answers: 1 Comments: 1

In the figure shown, m slides on inclined surface of wedge M. If velocity of wedge at any instant be v, find velocity of m with respect to ground.

$$\mathrm{In}\:\mathrm{the}\:\mathrm{figure}\:\mathrm{shown},\:{m}\:\mathrm{slides}\:\mathrm{on} \\ $$$$\mathrm{inclined}\:\mathrm{surface}\:\mathrm{of}\:\mathrm{wedge}\:{M}.\:\mathrm{If}\:\mathrm{velocity} \\ $$$$\mathrm{of}\:\mathrm{wedge}\:\mathrm{at}\:\mathrm{any}\:\mathrm{instant}\:\mathrm{be}\:{v},\:\mathrm{find} \\ $$$$\mathrm{velocity}\:\mathrm{of}\:{m}\:\mathrm{with}\:\mathrm{respect}\:\mathrm{to}\:\mathrm{ground}. \\ $$

Question Number 20035 Answers: 1 Comments: 1

In the following cases, find out the acceleration of the wedge and the block, if an external force F is applied as shown. (Both pulleys and strings are ideal)

$$\mathrm{In}\:\mathrm{the}\:\mathrm{following}\:\mathrm{cases},\:\mathrm{find}\:\mathrm{out}\:\mathrm{the} \\ $$$$\mathrm{acceleration}\:\mathrm{of}\:\mathrm{the}\:\mathrm{wedge}\:\mathrm{and}\:\mathrm{the}\:\mathrm{block}, \\ $$$$\mathrm{if}\:\mathrm{an}\:\mathrm{external}\:\mathrm{force}\:{F}\:\mathrm{is}\:\mathrm{applied}\:\mathrm{as} \\ $$$$\mathrm{shown}.\:\left(\mathrm{Both}\:\mathrm{pulleys}\:\mathrm{and}\:\mathrm{strings}\:\mathrm{are}\right. \\ $$$$\left.\mathrm{ideal}\right) \\ $$

Question Number 20014 Answers: 0 Comments: 1

A person in lift is holding a water jar, which has a small hole at the lower end of its side. When the lift is at rest, the water jet coming out of the hole hits the floor of the lift at a distance d of 1.2 m from the person. In the following, state of the lift′s motion is given in List I and the distance where the water jet hits the floor of the lift is given in List II. Match the statements from List I with those in List II. List I P. Lift is accelerating vertically up Q. Lift is accelerating vertically down with an acceleration less than the gravitational acceleration R. Lift is moving vertically up with constant speed S. Lift is falling freely List II 1. d = 1.2 m 2. d > 1.2 m 3. d < 1.2 m 4. No water leaks out of the jar

Question Number 19986 Answers: 1 Comments: 0

An aeroplane has to go from a point A to point B, 500 km away due 30° east of north. A wind is blowing due north at a speed of 20 ms^(−1) . The air speed of the plane is 150 ms^(−1) . Find the direction in which the pilot should head the plane to reach point B.

$$\mathrm{An}\:\mathrm{aeroplane}\:\mathrm{has}\:\mathrm{to}\:\mathrm{go}\:\mathrm{from}\:\mathrm{a}\:\mathrm{point}\:{A} \\ $$$$\mathrm{to}\:\mathrm{point}\:{B},\:\mathrm{500}\:\mathrm{km}\:\mathrm{away}\:\mathrm{due}\:\mathrm{30}°\:\mathrm{east} \\ $$$$\mathrm{of}\:\mathrm{north}.\:\mathrm{A}\:\mathrm{wind}\:\mathrm{is}\:\mathrm{blowing}\:\mathrm{due}\:\mathrm{north} \\ $$$$\mathrm{at}\:\mathrm{a}\:\mathrm{speed}\:\mathrm{of}\:\mathrm{20}\:\mathrm{ms}^{−\mathrm{1}} .\:\mathrm{The}\:\mathrm{air}\:\mathrm{speed}\:\mathrm{of} \\ $$$$\mathrm{the}\:\mathrm{plane}\:\mathrm{is}\:\mathrm{150}\:\mathrm{ms}^{−\mathrm{1}} .\:\mathrm{Find}\:\mathrm{the}\:\mathrm{direction} \\ $$$$\mathrm{in}\:\mathrm{which}\:\mathrm{the}\:\mathrm{pilot}\:\mathrm{should}\:\mathrm{head}\:\mathrm{the} \\ $$$$\mathrm{plane}\:\mathrm{to}\:\mathrm{reach}\:\mathrm{point}\:{B}. \\ $$

Question Number 19970 Answers: 0 Comments: 4

The velocity-time graph of a body is shown in figure. The displacement covered by the body in 8 seconds is

$$\mathrm{The}\:\mathrm{velocity}-\mathrm{time}\:\mathrm{graph}\:\mathrm{of}\:\mathrm{a}\:\mathrm{body}\:\mathrm{is} \\ $$$$\mathrm{shown}\:\mathrm{in}\:\mathrm{figure}.\:\mathrm{The}\:\mathrm{displacement} \\ $$$$\mathrm{covered}\:\mathrm{by}\:\mathrm{the}\:\mathrm{body}\:\mathrm{in}\:\mathrm{8}\:\mathrm{seconds}\:\mathrm{is} \\ $$

Question Number 19890 Answers: 1 Comments: 0

A man on top of a tower of height 35m throws a stone vertically upwards with a speed of 14m/s. Find: (i)the height above the ground, reached by the stone. (ii)the speed of the stone,when it reaches the ground.

$${A}\:{man}\:{on}\:{top}\:{of}\:{a}\:{tower}\:{of}\:{height} \\ $$$$\mathrm{35}{m}\:{throws}\:{a}\:{stone}\:{vertically} \\ $$$${upwards}\:{with}\:{a}\:{speed}\:{of}\:\mathrm{14}{m}/{s}. \\ $$$${Find}: \\ $$$$\left({i}\right){the}\:{height}\:{above}\:{the}\:{ground}, \\ $$$${reached}\:{by}\:{the}\:{stone}. \\ $$$$\left({ii}\right){the}\:{speed}\:{of}\:{the}\:{stone},{when} \\ $$$${it}\:{reaches}\:{the}\:{ground}. \\ $$

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