Physics Answers

A block of mass M = 10 kg is sitting on a surface inclined at angle θ = 45°. Given that the
coefficient of static friction is μ = 0.5 between block and surface, what is the minimum
force F necessary to prevent slipping? What is the maximum force F that can be exerted
without causing the block to slip?

On the horizontal surface of the table there is a chain of six identical bars connected by light threads. The coefficient of friction between the bars and the table is 0.2. Under the action of the horizontal force F = 8 N, the bars move along the table with acceleration. Find the thread tension between the 3 and 4 bars.

A load weighing 2 kg hangs on two light ropes of 30 cm and 50 cm. The ropes are attached to the horizontal ceiling, the angle between the ropes is 90°. Find the pulling force of the short rope. Take g = 10 m/s^2.

The load suspended on an elastic spring vibrates along the vertical with an amplitude of 4 cm and a period of 0.6 s. The load is at a distance of 27 cm from a thin converging lens with a focal length of 18 cm. Oscillations occur near the horizontal main optical axis of the lens. The mass of the spring is much less than the mass of the load. Find the maximum speed of the image of the load on the screen. Express the answer in centimeters per second (cm/s).

A worker can supply a maximum pull 150 lb on a cart which has a handle set at an angle
of 40o
above the horizontal. What is the coeficient of friction if he can just move a total
load 1,500lb?

In the cylinder under the piston there is a liquid and its saturated vapor. With isothermal expansion, the volume of steam increased by 8.4 times, and the pressure decreased by 2.1
times. Find the ratio of liquid mass to vapor mass before expansion.

There is a block on a horizontal surface. Coefficient of friction between the bar and the surface 0.2. If a force F is applied to the bar, directed upwards at an angle of 30° to the horizon, then the bar will move uniformly and rectilinearly along the table. Find the acceleration of the bar if a force of 1.4 N is applied to it in the same direction. Take g = 10 m/s^2.

An aqueous solution contains 30.0 g of a protein in 1.00 L. The osmotic pressure of the solution is 0.0167 atm at 27oC. What is the approximate molar mass of the protein?

A balloon with a volume of 1000m^3 has a shell with a mass of 160kg. The ball is filled with hot air at a temperature of 90°С. Outside air temperature 15°С. The shell of the ball is inextensible and has a hole in the lower part. Outside pressure is equal to normal atmospheric pressure. What is the maximum weight this ball can lift?