Recent questions tagged class11

An aeroplane is moving with horizontal velocity u at a height h. The velocity of a packet dropped from it on the earth's surface will be

asked Jul 3, 2013 by meena.p

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A police jeep is chasing with velocity $45 km/hr$ a thief in another jeep moving with velocity $153\;km/hr$. The police fires a bullet with muzzle velocity 0f $180\; m/s$. The velocity with which it will strike the car of the thief is

asked Jul 3, 2013 by meena.p

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For any complex number $z$ the minimum value of $|z|+|z-1|$ is ?

asked Jul 2, 2013 by rvidyagovindarajan_1

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A stone is dropped from top of a tower when it crosses a point 5 m below the top, another stone is let fall from a point 25 m below the top. Both stones reach the bottom of tower simultaneously. The height of tower is $(g=10 m/s^2)$

asked Jul 2, 2013 by meena.p

1 answer

Two diamonds begin a free fall from rest from same height $1.0 \; sec$ apart How long after will the two diamonds be 10 m apart ? $(g=10 m/s)$

asked Jul 2, 2013 by meena.p

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Two trains each having speed $30 km/hr$ are leading towards each other on the same straight track. A bird can fly at $ 60 km/hr$ flies off one train when they are $60 km$ apart and heads directly for the other train. On reaching other train it files directly back to first and so on. How many trips can the bird fly from one train to another before the trains crash?

asked Jul 2, 2013 by meena.p

1 answer

A particle moves in the plane according to the law $x=kt$, $y=kt(1- \alpha t)$ where $k$ and $\alpha$ are positive constants, t is time. The particle trajectory $ y(x) $ is

asked Jul 2, 2013 by meena.p

1 answer

The number of solutions of the equation $z^2+\overline {z}=0$ is

asked Jul 2, 2013 by rvidyagovindarajan_1

1 answer

A rocket is fired vertically up from the ground with a resultant vertical acceleration of $10 m/s^2$. The fuel is finished in 1 minute. and it continuous to move up. What is the maximum height reached?

asked Jul 2, 2013 by meena.p

1 answer

A partical A is projected with an initial velocity of $60 m/s$ at an angle $30 ^{\circ}$ to horizontal . At the same time a second particle B is projected in the opposite direction with initial speed of $50 m/s$ from a point at a distance of $100 m$ from A. If the particle collide in mid air. find the angle of projection $\alpha$ of particle B.$(g=10 m/s^2)$

asked Jul 2, 2013 by meena.p

1 answer

A body is thrown horizontally from top of a tower and strikes the ground after three seconds at an angle $45^{\circ}$ with horizontal. Find the height of the tower and initial speed of body.

asked Jul 2, 2013 by meena.p

1 answer

There are two angles of projection for which the horizontal range is same. The sum of maximum heights for these two angles is

asked Jul 2, 2013 by meena.p

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An open lift is moving upward with velocity $10 m/s$. It has an upward acceleration of $2 m/s^2$ . A ball is projected upward with velocity $20 m/s$ relative to ground. What is displacement of lift and ball at a time when ball meets the lift.

asked Jul 2, 2013 by meena.p

1 answer

Velocity of a particle moving in a straight line varies with its displacement as $v=(\sqrt {4 +4s}) m/s$. Displacement of particle at time t=0 is s=0. The displacement of particle at time t=2s is

asked Jul 2, 2013 by meena.p

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The acceleration of a particle moving in a straight line varies with its displacement as $a=2s$ velocity of particle is zero at zero displacement. The corresponding velocity displacement equation is

asked Jul 2, 2013 by meena.p

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A pendulum is released from $\theta_0=60 ^{\circ}$. The rate of change of speed of bob at $\theta=30 ^{\circ}$ is $(g=10 m/s^2)$

asked Jul 1, 2013 by meena.p

1 answer

A projectile is given an initial velocity of $\hat i+2 \hat j$. The cartesian equation of its path is $(g=10 m/s^2)$. ($\hat i$ vector along horizontal $\hat j$ vector along vertically upward)

asked Jul 1, 2013 by meena.p

1 answer

Ball A is dropped from top of a building. At same instant ball B is thrown vertically upwards from ground. When the balls collide, they were moving in opposite directions and speed of A is twice the speed of B. At what fraction of the height of building did the collision occur

asked Jul 1, 2013 by meena.p

1 answer

A ball is dropped from the roof of a tower of height h.The total distance covered by it in the last second of its motion is equal to the distance covered by it in first three seconds.The value of h is $(g=10 m/s^2)$

asked Jul 1, 2013 by meena.p

1 answer

A particle is released from rest from a tower of height 3h, the ratio of time of fall for equal heights h ie $t_1:t_2:t_3$ is

asked Jul 1, 2013 by meena.p

1 answer

The trajectory of a projectile in a vertical plane is $y=ax-bx^2$ where $a$ and $b$ are constants. The maximum height attained by the particle and the angle of projection from horizontal are

asked Jul 1, 2013 by meena.p

2 answers

A particle is projected up an inclined plane with initial speed $v=20 m/s$ at an angle $\theta=30 ^{\circ}$, with the plane. The component of its velocity perpendicular to plane when it strikes the plane is

asked Jul 1, 2013 by meena.p

1 answer

There are two values of time for which a projectile is at same height. The sum of these two times is

asked Jul 1, 2013 by meena.p

1 answer

Velocity versus displacement graph of a particle moving in a straight line is shown. corresponding acceleration versus velocity graph will be

asked Jul 1, 2013 by meena.p

1 answer

A very broad elevator is going up vertically with a constant acceleration of $2 m/s^2$. At the instant when its velocity is $4m/s$ a ball is projeted from the floor of the lift with a speed of $4 m/s$ relative to the floor at an elevation of $30 ^{\circ}$. The time taken by the ball to return to the floor is $(g=10 m/s^2)$

asked Jul 1, 2013 by meena.p

1 answer

A swimmer crosses a flowing stream of width 'w' to and fro in time $t_1$. The time taken to cross the same distance up and down the stream in $t_2.$ If $t_3$ is the time the swimmer would take to swim a distance $2w$ in still water. Then

asked Jun 29, 2013 by meena.p

1 answer

A particle moves in xy plane. The position vector of particle at any time t is $\overrightarrow r=\{(2t) i+(2t^2)j\}\; m$. The rate of change of $\theta$ at time $t= 2\;$ seconds is ( $\theta$ is the angle which its velocity vector makes with positive x-axis )

asked Jun 29, 2013 by meena.p

1 answer

A point moves in $X-Y$ plane according to $X=4 \sin \;6t $ and $Y=4(1-\cos \;6t)$.The distance traversed by the particle in 4 seconds is (x and y are in meters)

asked Jun 29, 2013 by meena.p

1 answer

Two buildings are 40m apart with what velocity should a ball be thrown horizontally from a window 145 m above the ground in one building so that it will enter a window $22.5 m$ above the ground in second building? $(g=9.8 m/s^2)$

asked Jun 29, 2013 by meena.p

1 answer

Two stones are projected horizontally from top of a tower in opposite directions with velocities $u_1$ and $u_2$. The time after which their displacement vectors are perpendicular to each other is

asked Jun 28, 2013 by meena.p

1 answer

A ball $B_1$ is projected from A at a velocity u making an angle $30 ^{\circ}$with the horizontal. Another ball $B_2$ is simultaneously projected from C verically up and with velocity v.Both collide each other at their maximum heights. What is ratio $\large\frac{u}{v}$

asked Jun 28, 2013 by meena.p

1 answer

A bullet fired into a plank loses half of its velocity after penetrating a thickness of $3 cm$. assuming that it has constant force of resistance, how much further does it penetrate before coming to rest

asked Jun 28, 2013 by meena.p

1 answer

A train starts from station A with uniform acceleration $\alpha$ for some distance and then goes with uniform retardation $\beta$ for some more time to come to rest at station B.The distance between station A and B is 4 km. and the train takes 4 minutes to complete this journey. If $\alpha$ and $\beta$ are in $km/min^2$ then

asked Jun 28, 2013 by meena.p

1 answer

Rain is falling vertically with a speed of $20\;ms^{-1}$. A person is running in rain (from east) with a velocity of $5 ms^{-1}$ and a wind is blowing with speed of $15ms ^{-1}$ (from west).The angle with the vertical at which the person should hold his umbrella is

asked Jun 28, 2013 by meena.p

1 answer

The displacement of a body is given to be proportional to the cube of time elapsed. The magnitude of acceleration of the body is

asked Jun 28, 2013 by meena.p

1 answer

A man moves along x axis such that velocity $v=\large\frac{1}{x}$. If he is initially at $x=2 m$ find the time when he reaches $x=4m$

asked Jun 28, 2013 by meena.p

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A river is flowing with speed of 1km/hr.A swimmer wants to go to point C starting from point A. He swims with a speed of 5 km/hr at an angle $\theta$with respect to the river. If $AB=BC=400m$ Then

asked Jun 28, 2013 by meena.p

1 answer

The figure gives the speed-time graph of the motion of a car. What is the ratio of the distance travelled by car during the last two seconds to total distance travelled in seven seconds

asked Jun 27, 2013 by meena.p

1 answer

A car starts with constant acceleration $ a=2 m/s^2$ at $t=0$ Two coins are released from the car at $t=3$ and $t=4$. Each coin takes 1 second to reach the ground.Then distance between two coins is (assume the coin stick to ground)

asked Jun 27, 2013 by meena.p

1 answer

The velocity of a particle is given by $v=5-t^2 m/s.$ The average acceleration of the particle between 3 and 5 seconds will be

asked Jun 27, 2013 by meena.p

1 answer

A motor boat is to reach at a point $30^{\circ}$ upstream on the otherside of river flowing with velocity $5m/s$. Velocity of motor boat with respect to water is $5 \sqrt3 m/s$ .The driver should steer the boat at an angle

asked Jun 27, 2013 by meena.p

1 answer

Starting from rest, a particle rotates in a circle of radius $R=\sqrt 2 m$ with an angular acceleration $a=\large\frac{\pi}{4} $$rad/s^2$. The magnitude of average velocity of particle over time when it rotates quarter circle is

asked Jun 27, 2013 by meena.p

1 answer

Average velocity of a particle moving in a straight line, with constant acceleration a, initial velocity u, time t is

asked Jun 27, 2013 by meena.p

1 answer

An elevator car whose floor to ceiling distance is 2.7 m starts ascending with constant acceleration of $1.2 m/s^2$ after 2 seconds of the start a bolt begins falling from ceiling of elevator. What is the time after which the bolt hits the floor of the elevator.

asked Jun 27, 2013 by meena.p

1 answer

A ball of mass m is attached to one end of a light rod of length $l$, other end of which is hinged . What minimum velocity 'v' should be imparted to the ball downwards so that it can complete the circle

asked Jun 27, 2013 by meena.p

1 answer

To a man walking at the rate of 3 km/hr the rain appears to fall vertically. When he increases the speed to 6 km/hr it appears to meet him at an angle of $45^{\circ}$ with vertical. Find the speed of rain.

asked Jun 26, 2013 by meena.p

1 answer

A particle is dropped from point A at a certain height from ground. It falls freely and passes through three points B,C and D with BC=CD.Time taken for particle to move from B to C is 2 seconds and from C to D is 1 second. Time taken to move from A to B is

asked Jun 26, 2013 by meena.p

1 answer

A particle A is projected from the ground with an initial velocity of 10 m/s at an angle $60 ^{\circ}$ with horizontal. From what height h should another particle B be projected horizontally with velocity 5 m/s. so both the particle collide in the ground at point C if both are projected simultaneously $(g=10 m/s^2)$

asked Jun 26, 2013 by meena.p

1 answer

Time taken to reach A to B for a projectile is 't'. Then the distance AB is equal to

asked Jun 26, 2013 by meena.p

1 answer

At a height 0.4 m from the ground the velocity of particle projected in angle $\theta$ is $\hat v=(6 i+ 2 j)m/s$ The angle of projection $\theta$ is $(g=10 m/s^2)$

asked Jun 26, 2013 by meena.p

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