Question

Два связанных между собой груза с массами 20 кг и 45 кг лежат на горизонтальной плоскости. К этим грузам приложены силы соответственно 145 и 15н, направленные в противоположные стороны. Какова сила натяжения нити, связывающей грузы, если коэффициент трения между грузами и плоскостью 0,08, а ускорение грузов 1,2 м/с²? ​

Answer 1

Ответ:

см фото

Объяснение:

Answer 2

Calculation of Tension Force in the String

To calculate the tension force in the string connecting the two masses, we need to consider the forces acting on each mass separately and apply Newton's second law of motion.

Let's denote the mass of the first object as m1 = 20 kg and the mass of the second object as m2 = 45 kg. The forces applied to these masses are F1 = 145 N and F2 = 15 N, respectively. The coefficient of friction between the masses and the horizontal surface is μ = 0.08, and the acceleration of the masses is a = 1.2 m/s².

We can start by calculating the net force acting on each mass:

For the first mass (m1 = 20 kg): The net force acting on m1 is the difference between the applied force F1 and the force of friction F_friction1: Net force on m1 = F1 - F_friction1

For the second mass (m2 = 45 kg): The net force acting on m2 is the difference between the applied force F2 and the force of friction F_friction2: Net force on m2 = F2 - F_friction2

To calculate the force of friction, we can use the equation: F_friction = μ * m * g where μ is the coefficient of friction, m is the mass, and g is the acceleration due to gravity (approximately 9.8 m/s²).

Now, let's calculate the force of friction for each mass:

For m1: F_friction1 = μ * m1 * g

For m2: F_friction2 = μ * m2 * g

Next, we can substitute the values and calculate the net forces:

For m1: Net force on m1 = F1 - F_friction1

For m2: Net force on m2 = F2 - F_friction2

Finally, we can calculate the tension force in the string connecting the masses. Since the masses are connected by the same string, the tension force in the string will be the same for both masses:

Tension force = Net force on m1 = Net force on m2

Let's calculate the tension force using the given values:

Step 1: Calculate the force of friction for each mass: F_friction1 = 0.08 * 20 kg * 9.8 m/s² F_friction2 = 0.08 * 45 kg * 9.8 m/s²

Step 2: Calculate the net forces on each mass: Net force on m1 = F1 - F_friction1 Net force on m2 = F2 - F_friction2

Step 3: Calculate the tension force in the string: Tension force = Net force on m1 = Net force on m2

Now, let's substitute the values and calculate the tension force:

Step 1: Calculate the force of friction for each mass: F_friction1 = 0.08 * 20 kg * 9.8 m/s² = 15.68 N F_friction2 = 0.08 * 45 kg * 9.8 m/s² = 35.28 N

Step 2: Calculate the net forces on each mass: Net force on m1 = F1 - F_friction1 = 145 N - 15.68 N = 129.32 N Net force on m2 = F2 - F_friction2 = 15 N - 35.28 N = -20.28 N

Step 3: Calculate the tension force in the string: Tension force = Net force on m1 = Net force on m2 = 129.32 N

Therefore, the tension force in the string connecting the masses is 129.32 N.