If the car is at constant speed, there is no net force. We will consider how far the car can go on 1 liter of gas. 107 J of work is available. One kilometer is 103 m so this is 20 km. Chapter 7 Review Questions 2.
Rotational inertia depends on mass and the distance of the mass from the axis of rotation.
A solid disk will have the greater acceleration rolling down a slope because the hoop has its mass farther from the axis of rotation so it will have more rotational inertia and be harder to start rolling. The lever arm is the distance from the axis of rotation to the point where the force is applied. The force should be applied perpendicular to the lever arm, or equivalently tangent to the circle that the point will rotate in, or equivalently, along the circle the point will rotate in. If a system is balanced, it will be in equilibrium and the clockwise and counterclockwise torques will be equal. Assuming the shoe box has its lid on, it will be in the center of the box.