Molecular Physics | Thermodynamics Answers

A soccer player takes a corner kick, lofting a stationary ball 30.0° above the horizon at 23.0 m/s. If the soccer ball has a mass of 0.425 kg and the player's foot is in contact with it for 3.90 ✕ 10⁻² s, find the x- and y-components of the soccer ball's change in momentum and the magnitude of the average force exerted by the player's foot on the ball.

(a)the x- and y-components of the soccer ball's change in momentum (in kg · m/s)

Δp_x= ___kg · m/s

Δp_y= ___kg · m/s

(b) the magnitude of the average force exerted by the player's foot on the ball (in N)

 __N

A 0.279-kg volleyball approaches a player horizontally with a speed of 12.1 m/s. The player strikes the ball with her fist and causes the ball to move in the opposite direction with a speed of 21.5 m/s.

(a) What impulse is delivered to the ball by the player? (Take the direction of final velocity to be the positive direction. Indicate the direction with the sign of your answer.)

___ kg · m/s

(b) If the player's fist is in contact with the ball for 0.0600 s, find the magnitude of the average force exerted on the player's fist.

___ N

Calculate the magnitude of the linear momentum for the following cases.

(a) a proton with mass 1.67  10^-27 kg, moving with a speed of 5.85  10⁶ m/s

 ___kg · m/s

(b) a 14.5-g bullet moving with a speed of 455 m/s

 ___kg · m/s

(c) a 74.0-kg sprinter running with a speed of 12.5 m/s

 ___kg · m/s

(d) the Earth (mass = 5.98  10²⁴ kg) moving with an orbital speed equal to 2.98  10⁴ m/s.

___ kg · m/s

A turbine operates under steady flow conditions, receiving steam at the following state: pressure 1200 kPa, temperature 188 degrees C, enthalpy 2785 kJ/kg, speed 33.3 m/s and elevation 3 m. The steam leaves the turbine at the following state; pressure 20 kPa, enthalpy 2512 kJ/kg, speed 100 m/s and elevation 0 m. Heat is lost to the surroundings at the rate of 0.29 kJ/s. If the rate of steam flow through the turbine is 0.42 kg/s, what is the power output of the turbine in kW?

An inventor claims to have invented a machine that is capable of manufacturing 50 jg / min of ice at -4 °C, from water at 20 °C and 1 bar of pressure, with an electrical energy consumption of kW (exergy). determine a) the heat flux that must be extracted to produce this ice flux, b) the optimal useful work of the process, c) if this machine is possible or not, d) if the machine is possible, the efficiency of the second law of it. the environment is at 20 °C and 1 bar

Water enters the condenser at 30^oC which has a mass of 10 kg/s. If heat added is 100 kW, determine the outlet temperature in KJ/s.