Question

A body weighing 10 kg begins to move and, after traveling 50 m, has a speed of 10 m / s. Find the friction coefficient if the thrust force is 14 N.

Answer 1

Дано: F тяги=14 Н; Vo=0; V=10 м/с; S=50 м; m=10 кг; k - ?
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Fтяги-Fтр=ma; F тр=kmg; S=(V^2-Vo^2)/2a=V^2/2a; a=V^2/2S;

kmg=Fтяги-m*V^2/2S; k=(F тяги-m*V^2/2S):mg=

(14-10*100/100):100=0,04.

Answer 2

To find the friction coefficient, we can use the concept of work-energy principle. The work-energy principle states that the work done on an object is equal to the change in its kinetic energy.

The work done by the thrust force is equal to the change in kinetic energy of the body. Mathematically, it can be expressed as:

Work done by thrust force = Change in kinetic energy

The initial kinetic energy of the body (when it begins to move) is zero since it starts from rest. The final kinetic energy can be calculated using the formula:

Final Kinetic Energy = 0.5 * m * v^2

where: m = mass of the body (10 kg) v = final speed of the body (10 m/s)

Now, we can find the work done by the thrust force:

Work done by thrust force = Final Kinetic Energy - Initial Kinetic Energy Work done by thrust force = 0.5 * m * v^2 - 0

Work done by thrust force = 0.5 * 10 kg * (10 m/s)^2 Work done by thrust force = 0.5 * 10 kg * 100 m^2/s^2 Work done by thrust force = 500 Joules

Next, we need to find the work done against friction. The work done against friction is equal to the force of friction multiplied by the distance traveled. Mathematically, it can be expressed as:

Work done against friction = Force of friction * Distance traveled

Given the distance traveled is 50 meters and the force of friction is 14 N, we can calculate the work done against friction:

Work done against friction = 14 N * 50 m Work done against friction = 700 Joules

Now, as per the work-energy principle, the work done by the thrust force is equal to the work done against friction:

Work done by thrust force = Work done against friction

So, we can equate the two values:

500 Joules = 700 Joules

However, this is not possible because the work done by the thrust force should be greater than the work done against friction for the body to accelerate. This discrepancy arises because we did not account for other external forces acting on the body, like gravity or air resistance.

If there are other forces at play, the problem becomes more complex, and we would need additional information to accurately calculate the friction coefficient. For example, we would need information about the time it took to travel the given distance or other forces acting on the body.

For now, based on the provided information, we cannot accurately determine the friction coefficient.