Q1 a box that has a mass of 4 kg is pushed with a force of...

Q1. A box that has a mass of 4 kg is pushed with a force of 20 N. The box accelerates at a rate of 2 m/s2, what is the force of friction in Newtons? just write the value Q.2 How much net force does it take to slow a 500 kg car from 20 m/s to 8 m/s in 3 seconds? Answer in Newtons, just the value.

Transcript

00:01 So in this question we have a box having mass m equals to 4 kilogram and it is pushed with the force f equals to 20 newton.

00:10 And the box is accelerating with a equals to 2 meter per second square.

00:15 So we have to determine the force of friction in the neutron.

00:19 So let us suppose this is the box which is placed on the rough horizontal surface.

00:25 And the pushing force f is this value and the xx.

00:30 Acceleration is in this direction and the friction force can be taken in this direction so we can write from the newton's law that is f minus small f that will be equals to mass multiplier b acceleration a okay so this will be weight m g in this direction so small f comes out to be capital f minus m a so capital f is 20 newton minus mass is 4kg multiple b acceleration is 2 meter per second square so friction force comes out to be 20 newton minus 8 newton okay so after solving this is equals to 12 newton okay so this become answered for the problem okay this is actually question one okay now we can solve for the question two in the same problem okay which says that we have to determine the net force taken by taken to slow the car having mass m equals to 500 kg from speed v1 equals to 20 meter per second to speed v2 equals to 8 meter per second and time t equals to 3 seconds okay so here the speed is reducing so we can calculate the acceleration so that will be given by v2 minus v1 divided by time t so 8 minus 20 divide by 3 so this comes out to be from here minus 4 meter per second is square.

02:00 So minus is representing that this is retardation.

02:04 Okay...

Question

Q1. A box that has a mass of 4 kg is pushed with a force of 20 N. The box accelerates at a rate of 2 m/s2, what is the force of friction in Newtons? just write the value Q.2 How much net force does it take to slow a 500 kg car from 20 m/s to 8 m/s in 3 seconds? Answer in Newtons, just the value.

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