91影视

Estimate the average power of a moving water wave that strikes the chest of an adult standing in the water at the seashore. Assume that the amplitude of the wave is 0.50 m, the wavelength is 2.5 m, and the period is 4.0 s.

A tsunami is a sort of pulse or 鈥渨ave packet鈥� consisting of several crests and troughs that become dramatically large as they enter shallow water at the shore. Suppose a tsunami of wavelength 235 km and velocity \(550\;{\rm{km/h}}\) travels across the Pacific Ocean. As it approaches Hawaii, people observe an unusual decrease of sea level in the harbors. Approximately how much time do they have to run to safety? (In the absence of knowledge and warning, people have died during tsunamis, some of them attracted to the shore to see stranded fishes and boats.)

What, roughly, is the percent uncertainty in the volume of a spherical beach ball of radius \({\bf{r = 0}}{\bf{.84 \pm 0}}{\bf{.04 m}}\)?

What is the area and its approximate uncertainty of a circle of the radius of \({\bf{3}}{\bf{.1}} \times {\bf{1}}{{\bf{0}}^{\bf{4}}}\;{\bf{cm}}\)?

What is the area and its approximate uncertainty of a circle of the radius of \({\bf{3}}{\bf{.1}} \times {\bf{1}}{{\bf{0}}^{\bf{4}}}\;{\bf{cm}}\)?

Write the following as full (decimal) numbers without prefixes on the units: (a) 286.6 mm, (b) 85 渭V(c) 760 mg, (d) 62.1 ps, (e) 22.5 nm, (f) 2.50 gigavolts.

Express the following using the prefixes of Table 1鈥�4:

(a) \({\bf{1 \times 1}}{{\bf{0}}^{\bf{6}}}\;{\bf{volts}}\)

(b) \({\bf{2 \times 1}}{{\bf{0}}^{{\bf{ - 6}}}}\;{\bf{meters}}\)

(c) \({\bf{6 \times 1}}{{\bf{0}}^{\bf{3}}}\;{\bf{days}}\)

(d) \({\bf{18 \times 1}}{{\bf{0}}^{\bf{2}}}\;{\bf{bucks}}\)

(e) \({\bf{7 \times 1}}{{\bf{0}}^{{\bf{ - 7}}}}\;{\bf{seconds}}\)

Express the following using the prefixes of Table 1鈥�4:

(a) \({\bf{1 \times 1}}{{\bf{0}}^{\bf{6}}}\;{\bf{volts}}\)

(b) \({\bf{2 \times 1}}{{\bf{0}}^{{\bf{ - 6}}}}\;{\bf{meters}}\)

(c) \({\bf{6 \times 1}}{{\bf{0}}^{\bf{3}}}\;{\bf{days}}\)

(d) \({\bf{18 \times 1}}{{\bf{0}}^{\bf{2}}}\;{\bf{bucks}}\)

(e) \({\bf{7 \times 1}}{{\bf{0}}^{{\bf{ - 7}}}}\;{\bf{seconds}}\)

One hectare is defined as \({\bf{1 \times 1}}{{\bf{0}}^{\bf{4}}}\;{{\bf{m}}^{\bf{2}}}\). One acre is \({\bf{4}}{\bf{.356 \times 1}}{{\bf{0}}^{\bf{4}}}\;{\bf{f}}{{\bf{t}}^{\bf{2}}}\). How many acres are there in one hectare?

One hectare is defined as \({\bf{1 \times 1}}{{\bf{0}}^{\bf{4}}}\;{{\bf{m}}^{\bf{2}}}\). One acre is \({\bf{4}}{\bf{.356 \times 1}}{{\bf{0}}^{\bf{4}}}\;{\bf{f}}{{\bf{t}}^{\bf{2}}}\). How many acres are there in one hectare?