A block of mass \(10\) kg, moving in the \(x\text-\)direction with a constant speed of \(10\) ms^-1, is subjected to a retarding force \(F=0.1x\) J/m during its travel from \(x =20\) m to \(30\) m. Its final kinetic energy will be:

A body of mass m dropped from a height h reaches the ground with a speed of 1.4$\sqrt{\mathrm{gh}}$. The work done by air drag is:

1. –0.2mgh 

2. –0.02mgh

3. –0.04mgh 

4. mgh

A force of 5 N making an angle $\theta$ with the horizontal acting on an object displaces it by 0.4 m along the horizontal direction. If the object gains kinetic energy of 1 J then the component of the force is:

The energy required to accelerate a car from rest to 30 m/s is E. The energy required to accelerate the car from 30 m/s to 60 m/s will be:

According to the work-energy theorem, the change in kinetic energy of a body is equal to work done by:

1.  Non-conservative force on the particle

2.  Conservative force on the particle

3.  External force on the particle

4.  All the forces on the particle

A block is carried slowly up an inclined plane. If \(W_f\) is work done by the friction, \(W_N\)${\mathrm{}}_{}$ is work done by the reaction force, \(W_g\) is work done by the gravitational force, and \(W_{ex}\) is the work done by an external force, then choose the correct relation(s):
1. \(W _N +   W _f   +   W _g   +   W _{ex}   =   0\)
2. \(W _N   =   0\)
3. \(   W _f   +   W _{ex}   =    - W _g\)
4. All of these

A particle of mass \(10\) kg moves with a velocity of \(10\sqrt{x}\) in SI units, where \(x\) is displacement. The work done by the net force during the displacement of the particle from \(x=4~\text{m}\) to \(x= 9~\text{m}\) is:
1. \(1250~\text{J}\)
2. \(1000~\text{J}\)
3. \(3500~\text{J}\)
4. \(2500~\text{J}\)

A block is released from rest from a height of \(h = 5 ~\text m.\) After traveling through the smooth curved surface, it moves on the rough horizontal surface through a length \(l = 8 ~\text m\) and climbs onto the other smooth curved surface at a height \(h'.\) If $\mathrm{}$\(μ = 0.5,\) then the height \( h'\) is:

A man pushes a wall and fails to displace it. He does:
1. negative work
2. positive but not maximum work
3. no work at all
4. maximum work