Work Energy and...

The energy stored in wound watch spring is 

 Two springs have their force constant as $$ k_1 $$ and $$ k_2( k_1 > k_2) $$ When they are stretched by the same force 

A particle moves under the effect of a force $$ F =Cx $$ from $$ x = 0 $$ to $$ x =x_1 $$ The work done process is 

If velocity of a body is twice of previous velocity, then kinetic energy will become

A spring $$ 40 $$ mm long is stretched by the application of a force. If $$ 10$$  N force required to stretch the spring through $$ 1 $$ mm, then work done in stretching the spring through $$ 40 $$ mm is 

An object of $$m\ kg$$ with speed of $$v\ m/s$$ strikes a wall at an angle $$\theta$$ and rebounds at the same speed and same angle. The magnitude of the change in momentum of the object will be 

A body of mass$$  3 $$kg is under a force, which causes a displacement  in it is given by $$ S = \frac {t^3}{3}  ( in m ) $$ find the work done by the force in first $$ 2 $$ seconds

A spring of spring constant $$ 5 \times 10 N/m $$ is stretched initially by $$ 5 $$ cm form the unstretched position. Then the work required to stretch it further by another  $$ 5 Cm $$ is 

The decrease in the potential energy of a ball of mass $$ 20 kg $$ which falls from a height of $$ 50 cm  $$ is  

The maximum velocity at the lowest point, so that the string just slack at the highest point in a vertical circle of radius l