Questions from College Physics

Q: What is the average pressure on the soles of the feet of

What is the average pressure on the soles of the feet of a standing 90.0 kg person due to the contact force with the floor? Each foot has a surface area of 0.020 m2.

Q: (a) What thickness of cork would have the same R

(a) What thickness of cork would have the same R-factor as a 1.0 cm thick stagnant air pocket? (b) What thickness of tin would be required for the same R-factor?

Q: A 20.0 g lead bullet leaves a rifle at a

A 20.0 g lead bullet leaves a rifle at a temperature of 47.0°C and travels at a speed of 5.00 × 102 m/s until it hits a 6.0 kg block of ice at 0°C that is initially at rest on a frictionless surface....

Q: A metal rod with a diameter of 2.30 cm and

A metal rod with a diameter of 2.30 cm and length of 1.10 m has one end immersed in ice at 32.0°F and the other end in boiling water at 212°F. If the ice melts at a rate of 1.32 g every 175 s, what is...

Q: To pass a physical fitness test, Marcella must run 1.

To pass a physical fitness test, Marcella must run 1.00 km at an average speed of 3.33 m/s. She runs the first 0.500 km at an average of 4.20 m/s. What should be her average speed over the remaining 0...

Q: A star's spectrum emits more radiation with a wavelength of 700.

A star's spectrum emits more radiation with a wavelength of 700.0 nm than with any other wavelength. (a) What is the surface temperature of the star? (b) If the star's radius is 7.20 × 108 m, what p...

Q: Given a slab of material with area 1.0 m2 and

Given a slab of material with area 1.0 m2 and thickness 2.0 × 10−2 m, (a) what is the thermal resistance if the material is asbestos? (b) What is the thermal resistance if the material is iron? (c)...

Q: A 3.0 L container of nitrogen gas (N2)

A 3.0 L container of nitrogen gas (N2) and a 5.0 L container of oxygen gas (O2) are both at 20°C and 1.0 atm. (a) Which gas has the larger rms speed? Explain. (b) At what temperature will oxygen gas...

Q: A free neutron (i.e., a neutron on its

A free neutron (i.e., a neutron on its own rather than in a nucleus) is not a stable particle. Its average lifetime is 15 min, after which it decays into a proton, an electron, and an antineutrino. Us...

Q: A copper rod of length 0.50 m and cross-

A copper rod of length 0.50 m and cross-sectional area 6.0 × 10−2 cm2 is connected to an iron rod with the same cross section and length 0.25 m. One end of the copper is...