Recent questions tagged unit2

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

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

1 answer

A juggler maintains four balls in motion making each of them raise to a height of 20m from his hand.What time interval should he maintain, for the proper distance between them $(g=10 m/s^2)$

asked Jun 26, 2013 by meena.p

1 answer

In a car race, car A takes less time to finish than car B and passes finishing point with a velocity $v_0$ more than velocity of car B and $t_0$ time earlier than car B. The cars starts from rest and travel with acceleration $a_1$ and $a_2$ respectively. Then ratio of $\large\frac{v_0}{t_0}$ is

asked Jun 26, 2013 by meena.p

1 answer

Two particles start moving from the same point in a straight line. The first moves with constant velocity v and second moves with constant acceleration a. During the time that elapses before the second catches the first, the greatest distance between the particle is

asked Jun 26, 2013 by meena.p

1 answer

A particle is projected vertically from a point A on ground. It takes time $t_1$ to reach point B but still continous to move up. It takes further $t_2$ time to reach the ground from point B. Height of point B from the ground is

asked Jun 26, 2013 by meena.p

1 answer

The velocity time (v-t) graph of a moving object is given by the following figure. The maximum acceleration is

asked Jun 25, 2013 by meena.p

1 answer

A particle is moving in x-y plane with $y=\large\frac{x}{2}$ and $v_x=4-2t$. The displacement versus time of the particle would be

asked Jun 25, 2013 by meena.p

1 answer

A 2m wide truck is moving with a uniform speed of $v_0=8 m/s$ along a staright horizontal road. A pedestrian starts to cross the road with a uniform speed of v when the truck is 4m away from him. The minimum value of 'v' so that he can cross the road safely is

asked Jun 25, 2013 by meena.p

1 answer

Two cars start off to race with velocities 4m/s and 2 m/s and travel in straight line with uniform acceleration $1\; m/s^2$ and $2 m/s^2$ respectively. If they reach the final point at same time, then the length of path is

asked Jun 25, 2013 by meena.p

1 answer

A body travelling along a straight line traversed one third of the total distance with velocity 4 m/s. The remaining part of distance was covered with a velocity $2 m/s$ for half the time and with velocity 6 m/s for other half of time. the mean velocity averaged over whole time of motion.

asked Jun 25, 2013 by meena.p

1 answer

A particle starts from rest at $t=0$ and undergoes an acceleration 'a' in $m/s^2$ with 't' in sec as shown

asked Jun 25, 2013 by meena.p

1 answer

$v_A=(x \hat i+6 \hat j) m/s,v_B=(3 \hat i+2 \hat j) m/s$ find x such that the relative speed of A with respect to B becomes 5 m/s

asked Jun 25, 2013 by meena.p

1 answer

For a motion with constant acceleration which is/are correct?

asked Jun 25, 2013 by meena.p

1 answer

A freely falling body is found to cover $7/16 ^{th} $ of the height of fall during the last second of its motion.Find the height from which it falls $(g=10m/s^2)$

asked Jun 24, 2013 by meena.p

1 answer

A ball is projected horizontaly with a speed v from top of a plane inclined at an angle $45^{\circ}$ with the horizontal. How far from the point of projection will the ball strike the plane

asked Jun 24, 2013 by meena.p

1 answer

A ball is dropped vertically from a height 'd' above the ground. it hits the ground and bounces up vertically to a height $d/2$ neglecting air resistance its velocity 'v' varies with height 'h' above the ground as

asked Jun 24, 2013 by meena.p

1 answer

The time taken by a particle to slide down a smooth inclined plane is double the time it would take in falling down along a height equal to vertical height of the plane. The inclination of the plane with horizontal is

asked Jun 24, 2013 by meena.p

1 answer

A man holds four balls 180 m above the ground and drops them at regular intervals of time so that when the first ball hits ground, fourth ball is just leaving his hand. At this time the second and third balls from the ground are at the positions.

asked Jun 24, 2013 by meena.p

1 answer

A river is flowing with a speed of 1km/hr. A swimmer wants to go to point 'C'. Starting from 'A', he swims with a speed of 5 km/hr at an angle $ \theta$ w.r.t the river. If $AB=BC=400 m$. Then

asked Jun 24, 2013 by meena.p

1 answer

Two fixed frictionless inclined planes making angle $30 ^{\circ}$ and $60 ^{\circ}$ with the vertical are shown. Two blocks A and B are placed on the two planes. What is the relative vertical acceleration of A with respect to B

asked Jun 24, 2013 by meena.p

1 answer

A car travelling with a speed of 60 km/hr can brake to stop within a distance of 20m. If the car is going twice as fast, the stopping distance will be ?

asked Jun 24, 2013 by meena.p

1 answer

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