Task 1.5
A body weighing 2 kg moves with an acceleration varying according to the law a = 5t-10. Determine the force acting on the body 5 seconds after the start of the action, and the speed at the end of the fifth second.

Task 1.15
The intrinsic lifetime of the pion is 2.6 • 10-8 s. What is the lifetime of the π meson for the observer, with respect to which this particle moves with a velocity of 0.8 s?

Task 1.25
The hoop and disc roll down from an inclined plane making an angle of 30 ° with the horizon. What are their accelerations at the end of the descent? The force of friction is neglected.

Task 1.35
Determine the speed of an electron if its relativistic mass is three times larger than the rest mass. Calculate the kinetic and total energy of the electron.

Task 1.45
In a 50 liter container, compressed hydrogen is stored at 27 ° C. After some of the air was released, the pressure dropped by 1 • 105 Pa. Determine the mass of hydrogen released. The process is considered isothermal.

Task 1.55
Determine the coefficient of internal friction of oxygen at a temperature of 400 K.

Task 1.65
Oxygen, occupying a volume of 10 liters and under pressure of 2 • 105 Pa, is adiabatically compressed to a volume of 2 liters. Find the work of compressing and changing the internal energy of oxygen.

Task 1.75
The refrigeration machine operates on the reverse Carnot cycle, efficiency. Which is 400%. What will be the c. Etc. of this machine, if it works in a direct Carnot cycle.