Problem of friction

Here is the asking problem: A car is stopped with its front wheels resting against a curb when its driver starts the engine and tries to drive over the curb. Knowing that the radius of the wheels is 280 mm, that the coefficient of static friction between the tires and the pavement is 0.90, and that 60 percent of the weight of the car is distributed over its front wheels and 40 percent over its rear wheels, determine the largest curb height h that the car can negociate, assuming (a) front-wheel drive, (b) rear-wheel drive. The answer of this problem for verification is: 71.9 mm for (a) and 39.9 mm for (b)

From 'net torque = I alpha', and angular momentum as a cross product, express conservation of angular momentum and solve an example.

PART a. A small mass m is attached to one end of a rod of negligible mass. The other end of the rod is fixed so that the mass can move in a circle of radius R. A force F is applied tangent to the circle, giving the mass angular acceleration 'alpha'. SEE ATTACHMENT #1 for a diagram showing parameters. Apply 'net torque= I alpha' to express the torque in terms of the moment of inertia and the angular velocity. PART b. Example: A uniform thin ring, mass M, radius R, is rotating about an axis at its center with initial angular velocity. At some instant it breaks and rearranges into a straight bar rotating about its center with final angular velocity. Apply conservation of angular momentum... click for more

Conservation of angular momentum of a sphere and ring changing to a sphere plus bars.

SEE ATTACHMENT #1 for a diagram of the system. A uniform sphere, mass M= 84 kg, radius R, has two uniform, thin, flexible bars each with mass m= 25 kg, and length half a circumference, wrapped on its surface as shown in Fig. 1. The system is rotating with a period To about a c.m. axis at center. At some instant, the bars fly outward to form a new configuration shown in Fig. 2. Find the ratio of the final period Tf to the initial period To.

Moment of inertia of a rod

Find the moment of inertia of a thin rod relative to the axis which is perpendicular to the rod and passes through its end, if the mass of the rod is m and its length l.

Calculating the final temperature of a gas undergoing an expansion at constant pressure, isothermally and according to the law where pv^1.25=Constant.

A perfect gas occupying 0.2 cubic meters at a pressure of 1240 Kpa and a temp of 150 deg Celsius is expanded to 0.5 cubic meters. What is the final temp if the expansion takes place in the following ways: at constant pressure, Isothermally and according to the law pv^1.25=Constant?