Question

Тело массой 20кг движется со скоростью 72 км в час и сцепляется с телом массой 30кг, которое движется со скоростью 10 м в секунду. Найти их общую скорость, если тела А)движутся в одном направлении, Б) движутся навстречу друг другу.

Answer 1

U--? m1=20 кг m2=30 кг V1=20 м/с V2=10 м/с А)m1V1-m2V2=U(m2-m1) U=m1V1-m2V2/m2-m1=20•20-30•10/30-20 =10 м/с Б)m1V1+m2V2=U(m2+m1) U=m1V1+m2V2/m2+m1=20•20+30•10/30+ +20=14 м/с

Answer 2

Calculation of Total Velocity

To find the total velocity of the two bodies, we can use the formula:

V = (m1 * V1 + m2 * V2) / (m1 + m2)

where: - V is the total velocity - m1 and m2 are the masses of the bodies - V1 and V2 are the velocities of the bodies

Let's calculate the total velocity in two scenarios:

A) When the bodies are moving in the same direction:

Given: - Mass of body 1 (m1) = 20 kg - Velocity of body 1 (V1) = 72 km/h = 20 m/s - Mass of body 2 (m2) = 30 kg - Velocity of body 2 (V2) = 10 m/s

Using the formula, we can calculate the total velocity (V):

V = (m1 * V1 + m2 * V2) / (m1 + m2)

Substituting the given values:

V = (20 kg * 20 m/s + 30 kg * 10 m/s) / (20 kg + 30 kg)

Simplifying the equation:

V = (400 kg·m/s + 300 kg·m/s) / 50 kg

V = 700 kg·m/s / 50 kg

V = 14 m/s

Therefore, the total velocity of the two bodies when moving in the same direction is 14 m/s.

B) When the bodies are moving towards each other:

Given: - Mass of body 1 (m1) = 20 kg - Velocity of body 1 (V1) = 72 km/h = 20 m/s (assuming it is moving towards the other body) - Mass of body 2 (m2) = 30 kg - Velocity of body 2 (V2) = -10 m/s (assuming it is moving towards the other body)

Using the formula, we can calculate the total velocity (V):

V = (m1 * V1 + m2 * V2) / (m1 + m2)

Substituting the given values:

V = (20 kg * 20 m/s + 30 kg * (-10 m/s)) / (20 kg + 30 kg)

Simplifying the equation:

V = (400 kg·m/s - 300 kg·m/s) / 50 kg

V = 100 kg·m/s / 50 kg

V = 2 m/s

Therefore, the total velocity of the two bodies when moving towards each other is 2 m/s.

Please note that the direction of the velocity is important in this calculation. The positive sign indicates movement in one direction, while the negative sign indicates movement in the opposite direction.