A block of mass 2.0 kg is pushed down an inclined plane of inclination `37^0` with a force of 20N cting parallelto the incline. It is found tht the block moves on the incline with an acceleration of `10 m/s^2`. If the blcok started from rest, find the work done a. by the applied force in the first second b. by the weight of the block in the first second and c. by the frictional force acting on the block in the first second. Take `g=10 m/s^2`.

Answer

A, B, C

Explanation

`m=2kg, theta=37^0, F=20N, a=10m/sec^2`
at=1sec
So, `s=ut+1/2at^2=5m`

Work dne by the applied force
`W=Fscostheta^0=20xx5=100J`
b. `BC(h)=5sin37^0=3m`
so, work done by weight ltbr. `W=mgh`
2xx10xx3=60J`
So, frictioN/Al force,
`f=mgsintheta`
Work done by the friction forces
`W=fs costheta0^0=(mg sinthega)s`
`=20xx0.60xx5=-60J`