00:01
This question of person, a person is pushing a lawnmour at an angle of 45 degree with a force of 15 newton.
00:08
So this is the lawnmour and he is pushing it at an angle of 45 degree with a force of 15.
00:16
And the lawnmower has a mass of 6 kilograms and the coefficient of fission is 0 .1.
00:22
Then what is the gain in the kinetic energy of the lawnmower after 10 seconds? so the force is like this, 10, sorry, 15, newtons.
00:30
And this is at 45 degrees.
00:34
The coefficient of friction is 0 .1 because the friction x is the left direction, this is the arrow, and this is 6 kilograms.
00:42
And this travels from rest and definitely after 10 seconds, it gains some speed v.
00:50
And we need to find a change in the kinetic energy.
00:53
And we know that the work done by all the forces has changed in the kinetic energy.
00:58
So here the forces is the external 15.
01:01
And force the friction force and although there is a gravity in the normal reaction but we know that those are perpendicular to the direction of motion and as there is no work by them so this is the change in the kinetic energy this is what we need to find so if we flip the equation the change in the kinetic energy is worked done by 15 newton force so the 15 newton is going to be so worked by 15 newton is f dot d now point is how much distance it has traveled because that we know don't know but we can definitely find that because the time is given and uh all right interesting because even if that time is given we might not be able to find a distance because then we need to find the value of the acceleration so it's better that we don't use this entirely and we can find the acceleration and hence we can find a velocity because that's an easier way so okay so if you make the components of the force so that will be 15 cosine of 45 over here.
02:04
15 sign of 45 over here.
02:10
And the friction is already over here.
02:13
The normal reaction is over here.
02:14
And the weight is over here.
02:18
Okay...