00:01
Here in this given problem mass of the object that is m is equal to 20 kg height raised by 8, h is equal to 1 .0 m.
00:28
In the first part of the problem we have to find work done on the object that will be given by force applied on it which is equal to its gravitational weight means mg and distance travelled that is h.
00:47
So here it will be 20 multiplied by g which is 9 .8 multiplied by h which is 1.
00:56
So this work done calculated to be equal to 196 joules.
01:03
Answer for the first part of the problem.
01:05
Now in the second part the man will be pushing the box up an incline.
01:19
This is the incline at an angle 30 degree with the horizontal.
01:29
The box being pushed on it if the mass of the box m then its weight mg acting vertically down two components of this weight component perpendicular to the surface that is mg cos 30 degree and along the incline surface downward this is mg sin 30 degree.
02:00
So now the force required to move the box up the incline at constant speed that will be equal to its opposition means mg sin 30 degree only.
02:19
So for mass that is 20 kilogram g 9 .8 and we know sin 30 degree that is half.
02:29
So force required is 98 newton...