Question

Помогите срочно!!! Проезжая по выпуклому мосту, радиус кривизны которого 128 м, автомобиль в верхней точке давит на мост с силой модуль которой на 25% меньше модуля силы тяжести, действующей на автомобиль. Определите модуль скорости автомобиля.​

Answer 1

Ответ:

≈18 м/с

Объяснение:

R=128 м    N=0.75*m*g    v=?

===

N=m*g - F

F=m*v²/R

0.75*m*g=m*g - m*v²/R

v=√0.25*R*g)=√(0.25*128*10)≈18 м/с

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Answer 2

Calculation of the Car's Speed on a Convex Bridge

To determine the speed of the car as it travels over a convex bridge, we need to consider the forces acting on the car at the top of the bridge. Given that the radius of curvature of the bridge is 128 m and the car exerts a force on the bridge that is 25% less than the force of gravity acting on the car, we can proceed with the following steps:

1. Calculate the force of gravity acting on the car: - Let's assume the mass of the car is m. - The force of gravity acting on the car is given by F_gravity = m * g, where g is the acceleration due to gravity (approximately 9.8 m/s^2).

2. Calculate the force exerted by the car on the bridge: - The force exerted by the car on the bridge is 25% less than the force of gravity acting on the car. - Therefore, the force exerted by the car on the bridge is F_bridge = 0.75 * F_gravity.

3. Determine the speed of the car at the top of the bridge: - At the top of the bridge, the centripetal force acting on the car is provided by the force exerted by the car on the bridge. - The centripetal force is given by F_centripetal = m * v^2 / r, where v is the speed of the car and r is the radius of curvature of the bridge. - Equating the centripetal force to the force exerted by the car on the bridge, we have F_centripetal = F_bridge. - Substituting the values, we get m * v^2 / r = 0.75 * m * g. - Simplifying the equation, we find v^2 = 0.75 * g * r. - Taking the square root of both sides, we obtain v = sqrt(0.75 * g * r).

Now, let's calculate the speed of the car using the given values:

- Radius of curvature of the bridge, r = 128 m. - Acceleration due to gravity, g ≈ 9.8 m/s^2.

Substituting these values into the equation, we find:

v = sqrt(0.75 * 9.8 * 128) ≈ 11.76 m/s.

Therefore, the module of the car's speed is approximately 11.76 m/s.

Please note that the calculation assumes ideal conditions and neglects factors such as air resistance and friction.