Recent questions in Laws of Motion

Two masses $M_1$ and $M_2$ are attached to end of a string which passes over a pulley attached to the top of a double inclined plane. If $M_1$ and $M_2$ are $5 kg$ each. and the base angles are $30^{\circ}$ each. The tension in the string.

asked Jul 10, 2013 by meena.p

1 answer

A smooth block is released at rest on $45 ^{\circ}$ incline and then slides a distance 'd'. The time taken to slide is 'x' times as much to slide on rough incline than on smooth incline.The coefficient of friction is

asked Jul 10, 2013 by meena.p

1 answer

A block of mass m is in contact with the cart C as shown. The coefficient of static friction between the block and cart is $\mu$. The acceleration $\alpha$ of the cart that will prevent the block from falling satisfies

asked Jul 9, 2013 by meena.p

1 answer

A horizontal force of 10 N is necessary to just hold a block stationary against a wall. The coefficient of friction between the block and wall is $\mu$ The weight of the block is

asked Jul 9, 2013 by meena.p

1 answer

Two beads A and B move along a semicircular wire frame as shown. The beads are connected by an inelastic string which always remains tight. At an instant the speed of A is $u$ . $ \angle BAC=45^{\circ}$ and angle $BOC=75 ^{\circ}$ where O is center of the semicircular arc. The speed of bead B at that instant is

asked Jul 9, 2013 by meena.p

1 answer

With what acceleration 'a' should the box in the figure descend so that a body of mass M placed in it exerts a force $Mg/4$ on the base

asked Jul 9, 2013 by meena.p

1 answer

In the arrangement shown by what acceleration the boy must go up so that 100 kg block remains stationary on the wedge. The wedge is fixed and friction is absent, every where $(g=10 m/s^2)$

asked Jul 9, 2013 by meena.p

1 answer

Inside a horizontally moving box, a man finds that when an object is placed on a horizontal smooth table and released; it moves with an acceleration $10 m/s^2$ In this box if 1 kg body is suspended with a light string, the tension in the string in equilibrium position $(g=10 m/s^2)$

asked Jul 9, 2013 by meena.p

1 answer

A boy sitting on top berth in the compartment of a train which just going to stop in a railway station dops an apple aiming at open hand of his brother sitting vertically below his hands at a distance of 2m. The apple will fall

asked Jul 9, 2013 by meena.p

1 answer

A person sitting in an open car moving at constant velocity throws a ball vertically up into air. The ball falls

asked Jul 9, 2013 by meena.p

2 answers

A ball is moving with velocity v strikes a wall moving towards the ball with velociy u. An elastic impact lasts for t seconds. Find the mean elastic force acting on the ball

asked Jul 9, 2013 by meena.p

1 answer

A body of mass 2 kg is moving along x-direction with velocity 2m/s. If a force of 4N is acting on it along y direction for 1 second, then what will be the final velocity

asked Jul 8, 2013 by meena.p

1 answer

A man is standing stationary with respect to a horizontal conveyor belt that is accelerating with $1 m/s^2$. What is the net force on the man if the coefficient of static friction between man's shoes and belt is 0.2, upto what acceleration of belt can the man continue to be stationary relative to the belt? Mass of man$=65 kg; g=9.8 m/s^2$

asked Jul 8, 2013 by meena.p

1 answer

All surfaces are smooth in the figure. Find F such that block of mass m resting on a wedge of mass M remains stationary with respect to wedge

asked Jul 8, 2013 by meena.p

1 answer

A ball of mass 1 kg is at rest in position P by means of two light strings OP and RP. The string RP is now cut and the ball swing to position Q. If $\theta=45 ^{\circ}$ . Find the tension in the string OQ when RP is cut $(g=10 m/s^2)$

asked Jul 8, 2013 by meena.p

1 answer

A body A of mass 1kg is resting on a table and connected to body B and C as shown. The surface are smooth and string and spring are massless. The string is inextensible. Find the extension in the spring if force constant of spring $=k=50 N/m$ take $(g=10 m/s^2)$

asked Jul 8, 2013 by meena.p

1 answer

A fireman has to carry an injured person of mass 40 kg from the top of a building with the help of the rope which can with stand a load of 100 kg. The acceleration of the fireman if his mass is 80 kg will be

asked Jul 8, 2013 by meena.p

1 answer

A disk of mass 10 gm is kept horizontaly in air by firing bullets of mass 5 g each. each at the rate of 10/s. If the bullet rebounds with which the bullets are fired is

asked Jul 8, 2013 by meena.p

1 answer

An inclined plane is inclined at an angle $\theta$ when the block placed on it is just at the point of moving down the plane. What can be the minimum acceleration with which the block can be moved up the inclined plane.

asked Jul 8, 2013 by meena.p

1 answer

The system as shown is released from rest. Neglecting friction and masses of pulleys, spring & rope the spring gets elongated if

asked Jul 8, 2013 by meena.p

1 answer

A horizontal force F is applied on a rod inserted between two identical blocks A and B placed over a rough surface as shown.Force F is gradually increased then which of the block will move first.

asked Jul 8, 2013 by meena.p

1 answer

An inclined plane makes an angle $30 ^{\circ}$ with horizontal. A groove $OA=5 m$ cut on the plane makes an angle $30 ^{\circ}$ with $OX$. A short smooth cylinder is free to slide down the groove under the influence of gravity. The time taken by the cylinder to reach from A to O is $(g=10 m/s^2)$

asked Jul 5, 2013 by meena.p

1 answer

A body of mass 50 kg is pulled by a rope of length 8 m on a surface by a force of 108 N applied at the other end. The force that is acting on the 50 kg mass, if the linear density of rope is 0.5 kg/m will be

asked Jul 5, 2013 by meena.p

1 answer

A block of mass M is pulled along a horizontal frictionless surface by a rope of mass m. If a force P is applied at the free end of the rope, the force exerted by the rope on the block will be

asked Jul 5, 2013 by meena.p

1 answer

A boy standing on a weighing machine observe his weight to be $200 N$. when he suddenly jumps upwards, his friend notice that the reading increased to $400 N$. The acceleration with which the boy jumped will be

asked Jul 5, 2013 by meena.p

1 answer

A lift is moving downward with an acceleration equal to acceleration due to gravity. A body of mass M kept on the floor of the lift is pulled horizontally. If the coefficient of friction is $\mu$, then the frictional resistance offered by the body is

asked Jul 5, 2013 by meena.p

1 answer

An object initially at rest explodes into three fragments. A,B and C The momentum of A is P$ \overrightarrow i $ that of B is $\sqrt 3$ P $\overrightarrow j$ where P is positive number. The momentum of C into be

asked Jul 5, 2013 by meena.p

1 answer

A $250 \;kg$ boat $4.5\;m$ long is floating with out motion on still water, with a boy of mass $50\; kg$ at one end. If he runs to the other end of the boat and stops, by how much distance the boat moves back?

asked Jul 5, 2013 by meena.p

1 answer

A ball of mass m strikes an identical ball at rest with speed of 10 m/s. After collision which is assumed perfectly elastic the first ball is found to move with speed 8 m/s. Speed of $2 ^{nd}$ ball and angle between the paths of two balls after collision is

asked Jul 5, 2013 by meena.p

1 answer

A shell of mass 'M' moving with velocity 'V' suddenly explodes into two fragments. One of the mass 'm' is reduced to rest. Find the velocity of the other fragment.

asked Jul 5, 2013 by meena.p

1 answer

A rocket burns fuel at the rate of $200 kg/s$. The exhaust gases are ejected down with a velocity of $400 m/s$. The upthrust developed by the rocket engine is

asked Jul 5, 2013 by meena.p

1 answer

A car of mass $2 \times 10 ^3 kg$ is to travel over a turn of radius $0.75 km$ and slope of angle $5^{\circ}$ If coefficient of friction between wheel and road is 0.5 maximum speed the car can travel with out slipping is $(\tan 5^{\circ}=0.087)$

asked Jul 5, 2013 by meena.p

1 answer

A body of mass $4 kg$ is at rest on a horizontal table. The coefficient of friction between body and table is 0.3 . Find the acceleration of the body if a horizontal force applied on the body is 20 N

asked Jul 4, 2013 by meena.p

1 answer

Two masses of $10\; kg$ and $20\; kg$ respectively are connected by a massless spring. A pull of $100 N$ acts on the mass $20 kg$. If the instantaneous acceleration of 10 kg mass is $2 m/s^2$, what is the acceleration of $20 kg$ mass

asked Jul 4, 2013 by meena.p

1 answer

A man pushes a truck initially at rest and weighting $2.5$ tonne along a horizontal rail with a steady force of $200 N$. The resistance to the motion amounts to $30 N$ per tonne. The velocity of the truck at the end of 30 seconds is

asked Jul 4, 2013 by meena.p

1 answer

A man fires the bullet of mass m each with a velocity v from a machine gun. If he fires n bullets every second, the reactional force per second on the man will be

asked Jul 4, 2013 by meena.p

1 answer

A force of $(6 \hat i+8 \hat j) N $ acted on a body of mass 10 kg.The displacement after 10 sec. if it starts from rest will be

asked Jul 4, 2013 by meena.p

1 answer

If the normal to force is doubled, the coefficient of friction is

asked Jul 4, 2013 by meena.p

1 answer

Two bodies of masses m$_1$ (4 kg) and m$_2$ (3 kg) are suspended at the ends of a string of negligible mass passing over a friction-less pulley as shown here.The acceleration of the system is

asked Jul 4, 2013 by meena.p

1 answer

The linear momentum p of a moving body varies with time according to equation $p=a+bt^2$ where a,b are constants. Net force acting on the body is

asked Jul 4, 2013 by meena.p

1 answer

A man of weight 1 mg is moving up in a rocket with an acceleration 4g. The apparent weight of the man in the rocket is

asked Jul 4, 2013 by meena.p

1 answer

If the tension in the cable of $1000 \;kg$ elevator is $1000\;kg$ weight, the elevator

asked Jul 4, 2013 by meena.p

1 answer

A car is moving with uniform velocity on a rough horizontal road.Then according to Newton's first law of motion

asked Jul 4, 2013 by meena.p

1 answer

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

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