Work Energy and...

A 0.25kg ball attached to a 1.5 m rope moves with a constant speed of 15 m/s around a vertical circle. Calculate the tension force on the rope at the middle of the circle:

two blocks of masses $$m_1 = 2 kg$$ and $$m_2 = 4 kg$$ are moving in the same direction with speeds $$\nu_1 = 6 m/s$$ and $$\nu_2 = 3 m/s$$, respectively on a frictioneless surface as shown in the figure. An ideal spring with spring constant $$k = 30000 N/m$$ is attached to the back side of $$m_2$$. Then the maximum compression of the spring after collision will be:

A particle of mass 1 kg is suspended by means of a string of length L=2 m. The string makes $$6/\pi$$ rps around a vertical axis through the fixed end. The tension in the string is

A mass attached to a string that is itself attached to the ceiling swings back and forth. If the bob is observed to be moving upward at a given instance, as shown to the right, which arrow best depicts the direction of the net force acting on the bob at that instant

When a rubber-bank is stretched by a distance $$x$$, it exerts a restoring force of magnitude $$F=ax+b{x}^{2}$$ where $$a$$ and $$b$$ are constants. The work done in stretching the unstretched rubber band by $$L$$ is:

A thin uniform rod of mass $$m$$ and length $$l$$ is hinged at the lower end of a level floor and stands vertically. It is now allowed to fall, then its upper and will strike the floor with a velocity given by(A)$$\sqrt { mgl }$$(B) $$\sqrt { 3gl }$$(c)$$\sqrt { 5gl }$$ (D) $$\sqrt { 2gl }$$  Sol. 

A body of mass $$1kg$$ thrown upwards with a velocity of $$10m/s$$ comes to rest (momentarily) after moving up by $$4m$$. The work done by air drag in this process is (Take $$g=10m/{ s }^{ 2 }$$)

A body is acted upon by force which is inversely proportional to the distance covered. The work done will be proportional to:

The work done by a force is equal to :

A particle of mass $$2\ kg$$ travels along a straight line with velocity $$v=a \sqrt {X}$$, where $$a$$ is a constant. The work done by net force during the displacement of particle from $$x=0$$ to $$x=4\ m$$ is: