Molecular Physics | Thermodynamics Answers

Given the atmospheric pressure to be 101.325 MPa, find the absolute pressure if the gauge pressure is:

1.1 Pg = 25 psi

1.2 Pg = 235 torr

A person stands at a point 358 m

 in front of the face of a sheer cliff. If the person shouts, how much time will elapse before an echo is heard? (Assume the speed of sound is 344 m/s.)

The sound level measured in a room by a person watching a movie on a home theater system varies from 50 dB

 during a quiet part to 90 dB

 during a loud part. Approximately how many times louder is the latter sound?

The leg and cast in the figure below weigh 280 N (w₁). Determine the weight w₂ and the angle 𝛼 needed so that no force is exerted on the hip joint by the leg plus cast

w₂ = ___ N

𝛼=  ___°

A block of mass 14.2 kg is sliding at an initial velocity of 6.15 m/s in the positive x-direction. The surface has a coefficient of kinetic friction of 0.153. (Indicate the direction with the signs of your answers.)

(a) What is the force of kinetic friction (in N) acting on the block?___ N

(b) What is the block's acceleration (in m/s²)? ___m/s²

Two gaseous streams enter a combining tube and leave as a single mixture. These data apply at the entrance section:

For one gas : A₁ = 55 cm² U₁ = 400fps    v1 = 10 ft³/lb_m

For another gas: A₂ = 50 cm²  m₂ = 12.22lb_m/s    р = 00.12lb_m/ft³

At exit section: U₃ = 350 fps      v₃ = 8ft³/lb_m

Find (a) U₂ at section 2 (b) mass flow rate at the exit

The number of valence electrons in a potassium ion. __,,,the number in a chloride ion is ____

A horse is harnessed to a sled having a mass of 241 kg, including supplies. The horse must exert a force exceeding 1260 N at an angle of 30.3° (above the horizontal) in order to get the sled moving. Treat the sled as a point particle.

(a) Calculate the normal force (in N) on the sled when the magnitude of the applied force is 1260 N. (Enter the magnitude.) __N

(b) Find the coefficient of static friction between the sled and the ground beneath it.

(c) Find the static friction force (in N) when the horse is exerting a force of 6.30 ✕ 10² N on the sled at the same angle. (Enter the magnitude.) __N

A rocket takes off from Earth's surface, accelerating straight up at 75.2 m/s². Calculate the normal force (in N) acting on an astronaut of mass 84.9 kg, including his spacesuit. (Assume the rocket's initial motion is parallel to the +y-direction. Indicate the direction with the sign of your answer.)

___N

A student of mass 59.4 kg, starting at rest, slides down a slide 24.2 m long, tilted at an angle of 20.1° with respect to the horizontal. If the coefficient of kinetic friction between the student and the slide is 0.108, find the force of kinetic friction, the acceleration, and the speed she is traveling when she reaches the bottom of the slide. (Enter the magnitudes.)

(a) the force of kinetic friction (in N) __ N

(b) the acceleration (in m/s²) ___m/s²

(c) the speed she is traveling (in m/s) ___ m/s