Acommonly used method of fastening one part to another part is called "shrink fitting." a steel rod has a diameter of 2.0024 cm, and a flat plate contains a hole whose diameter is 2. cm. the rod is cooled so that it just fits into the hole. when the rod warms up, the enormous thermal stress exerted by the plate holds the rod securely to the plate. by how many celsius degrees should the rod be cooled?

The steel rod should be cooled by 99.88°C

Explanation:

To solve this exercise we require the thermodynamic concept of thermal expansion.

Here it is necessary to have the coefficient of thermal expansion for steel, since the formula to calculate is:

Where

ΔL represents the change in length,

is the initial length,

α is the coefficient of thermal expansion

ΔT the change in temperature.

α of the steel is

The longitudinal change of our material is of

Replacing,

Solving to ,

Therefore the steel rod should be cooled by 99.88°C

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.