b) Самолет массой 75 т из состояния покоя разгоняется. Определите силу тяги 4-х двигателей самолета при разбеге самолета, если равнодействующая сил равна 120 кН и коэффициент тре трения 0,027
Based on the given information, the first step is to calculate the mass of each individual engine. This can be done by dividing the total mass of the plane (75 tons or 75,000 kg) by the number of engines (4), resulting in a mass of 18,750 kg per engine. Next, we need to find the acceleration of the plane during takeoff. This can be done using Newton's second law of motion: F = ma, where F is the sum of all the forces acting on the plane, m is the mass of the plane, and a is the acceleration. In this case, we know that the sum of all forces (equal to the net force) is 120 kN and the mass of the plane is 75,000 kg. Rearranging the formula, we get a = F/m = 120,000 N/75,000 kg = 1.6 m/s^2. This means that the plane is accelerating at a rate of 1.6 meters per second squared. From here, we can use the formula for frictional force (Ff = μN) to find the force of friction acting on the plane. The normal force (N) in this case is equal to the weight of the plane, which is calculated by multiplying the mass (75,000 kg) by the acceleration due to gravity (9.8 m/s^2). This gives us a normal force of 735,000 N. Now, plugging in the values for the coefficient of friction (μ = 0.027) and the normal force, we can calculate the force of friction, which comes out to be 19,845 N. To find the force of thrust, we simply need to subtract the force of friction from the net force acting on the plane. This gives us a thrust of 100,155 N. Therefore, the force of thrust for each engine would be 100,155 N divided by 4, resulting in a force of 25,039 N for each engine during takeoff.
