Work Energy Theorem Application

Q. A particle of mass m1 is moving with velocity v1 and another particle of mass m2 is moving with velocity v2.Both of them have the same momentum but different kinetic energy are E1 and E2.If m1 >m2 then 1)E1E2 4)E1=E2

Q. 8. The average force necessary to stop a hammer with momentum p Ns in 0.5s is

Q. { A particle is thrown with kinetic energy }k straight }}{ up a rough inclined plane of inclination }α and }}{ coefficient of friction }μ . The work done against }} friction before the particle comes to rest is

Q.

An open knife edge of mass m is dropped from a height h on a wooden

floor. If the blade penetrates upto the depth d into the wood, the average resistance offered by the wood to the knife edge is

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Q.

A force $F=(3x+4)$ displaces an object of mass $10kg$ from $x=0$ to $x=4m$ if the speed of the object at $x=0$ is 2m/sec then its speed at x=4m will be

1. $\sqrt{3}m/s$

2. $2\sqrt{3}m/s$

3. $3m/s$

4. $4m/s$

Q. 90.A projectile of mass 2 k.g. has velocity 3m/s and 4m/s at two points during its flight in the uniform gravitational field of the Earth. If these two velocities are perpendicular to each other, then the minimum kinetic energy of the particle during its flight is A)6.32 J. B)8.40 J. C)16.32 J. D)5.76 J.

Q. A particle of mass 200 g is moving in a circle ofradius 2 m. The particle is just looping the loop.The speed of the particle and the tension in the string at highest point of the circular path are

Q. 3. A force F(t) = 12 -a particle moving along x-axis. Starting from vparticle is taken along x-axis. Find the momentumof particle att = 10 s.3t (N) varying with time acts on0(1) -30i kg m/s(2) -20/ kg m/s(3) 30i kg m/s(4) 20i kg m/s

Q. If the error in measurement of momentum of a particle is 10% and mass is known exactly, the permissible error in kinetic energy is

Q. A force F = (31+4)N is acting on a point masskg at a point A (2m, 2m). Find the2angular acceleration of the line OA at this instant.(1) 1 rad/s2(2)rad/s2(3)rad/s2rad/s2()

Q. A rain drop of radius 2 mm falls from a height of 500 m above the ground. It falls with decreasing acceleration (due to viscous resistance of the air) until at half its original height, it attains its maximum (terminal) speed, and moves with uniform speed thereafter. What is the work done by the gravitational force on the drop in the first and second half of its journey ? What is the work done by the resistive force in the entire journey if its speed on reaching the ground is 10 m s¯¹?

Q. 23 A particle of mass m strikes elastically on a wall with velocity v, at an angle of 60 from the wall then magnitude of change in momentum of ball along the wall is

Q. how to convert weight into force( in newton) ?if a person weights 400N on earth, what is its mass?

Q. in finding work done by object moving upward on the inclinced plane then why we not minus friction force from the force applied

Q. A man applies a constant force of $5\text{N}$ on an object of mass $2\text{kg}$ and displaces it by $5\text{m}$. The object was initially at rest. The final velocity of object is

1. $10\text{m/s}$
2. $5\text{m/s}$
3. $25\text{m/s}$
4. $15\text{m/s}$

Q.

James Prescott Joule, after whom the unit of energy is named, wanted to prove that mechanical energy can be converted to thermal energy. To help him prove that, he created the setup as shown in the figure.

1kg of water is stored in an adiabatic container at ${15}^{\circ }C$. A paddle connected to a mass of 15 kgs through massless and frictionless pulleys, is immersed into the water.

At time t = 0s, the 15kg mass is allowed to fall. After 40s it was noticed that the mass had fallen by a height of 10 m and gained a velocity of 4 m/s. If Joule was successful in this experiment, what would be the temperature of the water at time t = 40s?

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Q. 9. If force of 200N acts on a body , the change in momentum is 100 kg m/s .what is the time for which the force acts in the body

Q. 19. If the error in the measurement of momentum of a particle is (+100%) then the error in the measurement of kinetic energy is: a) 100%. b) 200% c) 300%. d) 400%

Q. If the error in measurement of momentum of a particle is 10% and mass is known exactly , permissible error in measurement of kinetic energy is ?

Q. 43. A particle is thrown with kinetic energy 100J straight up on a rough inclined plane of inclination 45 degree and coefficient of friction is 0.2. The work done against friction before particle comes to rest is 16.6J 100J 13J 33.3J

Q. 31. A ball of mass m and radius r is tied to a string of length L. If it revolves in a horizontal circle with constant angular speed omega then the magnitude of torque acting on it is ??

Q. A pendulum consists of a wooden bob of mass $m$ and length $l$. A bullet of mass $m_1$ is fired towards the pendulum with a speed $V_1$ and it emerges from the bob with speed $\frac{V_1}{3}.$ The bob just completes motion along a vertical circle. Then $v_1$ is

1. $\frac{m_1}{m}\sqrt{5gl}$
   
2. $\frac{2m}{3m_1}\sqrt{5gl}$
   
3. $\frac{3m}{2m_1}\sqrt{5gl}$
   
4. $\frac{m}{m_1}\sqrt{5gl}$
   

Q. An aeroplanes velocity is doubled . what happens to its momentum and kinetic energy ?

Q.

The same retarding force is applied to stop a train. The train stops after 80 m. If the speed is doubled, then the distance will be

1. The same

2. Doubled

3. Halved

4. Four times

Q. A particle is released at point $P(-2\text{m},2\text{m})$ on a smooth parabolic track given by $y=\frac{x^2}{2}$. It slides down the track and leaves the contact with the track at point $Q(1\text{m},0.5\text{m})$, and then slides till point $R$ along $QR$. Distance $QR$ in m equals $(g=10{\text{m/s}}^2)$

Q. Consider a carnot cycle operating between T1=5ooK and T2=300K producing 1KJ of mechanical work per cycle.Find the heat transfer to engine by the reservoirs.

Q. 125.A body is moving on a rough horizontal surface with initial velocity V. If 3/4 of its kinetic energy is lost due to friction in time t, then what will be value of coefficient of friction. 1)V/2gt 2) V/gt 3) V/4gt 4) 4V/4gt

Q.

A block of mass 1 kg is placed at the point A of a rough track shown in figure. If slightly pushed towards right, it stops at the point B of the track. Calculate the work done by the frictional force on the block during its transit from A to B.

1. 2 J

2. 4 J

3. -2J

4. -4 J

Q. A truck starts from rest and accelerates uniformly at $2.0m{s}^{-2}$. At $t=10s$, a stone is dropped by a person standing on the top of the truck ($6m$ high from the ground). What are the (a) velocity, and (b) acceleration of the stone at $t=11s$ ? (Neglect air resistance.)

Q. A block of mass $8\text{kg}$, moving in x-direction with a constant speed of $15\text{m/s}$, is subjected to a retarding force of $F=10x\text{N}$ during its travel from $x=10\text{m}$ to $x=15\text{m}$. Find its final kinetic energy.

1. $300\text{J}$
2. $325\text{J}$
3. $275\text{J}$
4. $350\text{J}$