Question

В передний номерной знак автомобиля, движущегося со скоростью 80 км/ч, попадает резиновая пуля от травматического пистолета, летящая навстречу со скоростью 200 км/ч и отскакивает. С какой скоростью будет двигаться пуля относительно земли, если коэфициент восстановления скорости равен 0,8? И еще тот же вопрос, но на этот раз пуля попадает в задний номерной знак. Помогите

Answer 1

224 км/ч скорость пули.
200+80=280
280*0.8=224

Answer 2

Calculation of Bullet Speed After Rebound

To calculate the speed of the bullet after rebound, we can use the principle of conservation of momentum. The momentum of an object is the product of its mass and velocity. According to the principle of conservation of momentum, the total momentum before the collision is equal to the total momentum after the collision.

In this scenario, the bullet is initially moving towards the car with a speed of 200 km/h, and the car is moving towards the bullet with a speed of 80 km/h. The coefficient of restitution, which represents the elasticity of the collision, is given as 0.8.

Let's denote the mass of the bullet as m1 and the mass of the car as m2. Since the bullet rebounds, its final velocity will have an opposite direction to its initial velocity. The final velocity of the car will depend on the mass ratio between the bullet and the car.

Using the conservation of momentum, we can write the equation:

m1 * v1_initial + m2 * v2_initial = m1 * v1_final + m2 * v2_final

Where: - m1 is the mass of the bullet - v1_initial is the initial velocity of the bullet (200 km/h) - m2 is the mass of the car - v2_initial is the initial velocity of the car (80 km/h) - v1_final is the final velocity of the bullet - v2_final is the final velocity of the car

Since the bullet rebounds, its final velocity will be in the opposite direction, so v1_final = -v1_initial.

We can rearrange the equation to solve for v1_final:

v1_final = (m1 * v1_initial + m2 * v2_initial - m2 * v2_final) / m1

Now, let's substitute the given values: - v1_initial = 200 km/h - v2_initial = 80 km/h - v2_final = 0 km/h (since the car does not rebound)

We also need to consider the mass ratio between the bullet and the car. Unfortunately, the mass values are not provided in the question. Therefore, we cannot calculate the exact final velocity of the bullet without knowing the masses of the bullet and the car.

Please provide the masses of the bullet and the car so that we can calculate the final velocity of the bullet after rebound.

Calculation of Bullet Speed After Rebound (Alternative Scenario)

In the alternative scenario where the bullet hits the rear license plate, we can still use the principle of conservation of momentum to calculate the speed of the bullet after rebound.

Similar to the previous scenario, the bullet is initially moving towards the car with a speed of 200 km/h, and the car is moving towards the bullet with a speed of 80 km/h. The coefficient of restitution is still given as 0.8.

Using the conservation of momentum, we can write the equation:

m1 * v1_initial + m2 * v2_initial = m1 * v1_final + m2 * v2_final

Where: - m1 is the mass of the bullet - v1_initial is the initial velocity of the bullet (200 km/h) - m2 is the mass of the car - v2_initial is the initial velocity of the car (80 km/h) - v1_final is the final velocity of the bullet - v2_final is the final velocity of the car

Since the bullet rebounds, its final velocity will be in the opposite direction, so v1_final = -v1_initial.

We can rearrange the equation to solve for v1_final:

v1_final = (m1 * v1_initial + m2 * v2_initial - m2 * v2_final) / m1

Now, let's substitute the given values: - v1_initial = 200 km/h - v2_initial = 80 km/h - v2_final = 0 km/h (since the car does not rebound)

Again, we need the masses of the bullet and the car to calculate the exact final velocity of the bullet after rebound. Please provide the masses so that we can proceed with the calculation.