Under some circumstances, a star can collapse into an extremely dense object made mostly of neutrons and called a neutron star. the density of a neutron star is roughly 1014 times as great as that of ordinary solid matter. suppose we represent the star as a uniform, solid, rigid sphere, both before and after the collapse. the star's initial radius was 7.0×105km (comparable to our sun); its final radius is 18km . if the original star rotated once in 34 days, find the angular speed of the neuron star.

Ammonia enters the expansion valve of a refrigeration system at a pressure of 10 bar and a temperature of 18oc and exits at 6.0 bar. the refrigerant undergoes a throttling process. determine the temperature, in oc, and the quality of the refrigerant at the exit of the expansion valve.

What is the average speed of a car that travels 40mph for 1 hour and 60 mph in another hour will mark brainliest

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.