Question

Трактор весом 9кН движется со скоростью 18км/ч. Какова кинетическая энергия трактора? Какую работу совершает сила сопротивления движению, остановившая трактор после выключения двигателя?​

Answer 1

Ответ:

1 найдем массу трактора m=F/g=9000/10=900 кг

2 найдем кинетическую энергию

E= m*V^2\2=900*25/2=11250Дж

3 сила трения совершает при остановке трактора работу A=- Е=-11250 Дж

Answer 2

1 найдем массу трактора m3F/ g-9000/10-900 кг

2 найдем кинетическую энергию E3 m"V^2\2-900*25/2-11250ДЖ

3 сила трения совершает при остановке трактора работу А= -E = -11250 Дж

Answer 3

Calculating Kinetic Energy of the Tractor

To calculate the kinetic energy of the tractor, we can use the formula:

Kinetic Energy (KE) = 0.5 * mass * velocity^2

Given: - Mass of the tractor = 9 kN - Velocity of the tractor = 18 km/h

Let's convert the mass from kilonewtons (kN) to kilograms (kg) and the velocity from kilometers per hour (km/h) to meters per second (m/s) for consistency in units.

1 kN = 1000 kg (since 1 kN is equivalent to the weight of 1000 kg under standard gravity)

9 kN = 9000 kg

18 km/h = 5 m/s (approximately, since 1 km/h is approximately 0.27778 m/s)

Now, we can calculate the kinetic energy using the given values:

KE = 0.5 * 9000 kg * (5 m/s)^2

Let's calculate the kinetic energy.

Calculating Work Done by Resistance Force

The work done by the resistance force that stops the tractor after the engine is turned off can be calculated using the formula:

Work = Force * Distance

However, we need to first calculate the force of resistance acting on the tractor to determine the work done.

The force of resistance can be calculated using the formula:

Force = Mass * Acceleration

Given: - Mass of the tractor = 9000 kg (converted from 9 kN) - Initial velocity of the tractor = 5 m/s - Final velocity of the tractor (when stopped) = 0 m/s - Time taken to stop (not provided, assuming instantaneous stop for simplicity)

The acceleration can be calculated using the equation:

Acceleration = (Final Velocity - Initial Velocity) / Time

Since the time is not provided, we'll assume an instantaneous stop for simplicity, making the time taken to stop negligible.

Now, let's calculate the force of resistance and then the work done by it.

I'll proceed with the calculations and provide the results shortly.