| № |
Condition |
free/or 0.5$ |
| 55263 | The time it takes for an object dropped from the top of cliff A to hit the water in the lake below is twice the time it takes for another object dropped from the top of cliff B to reach the lake.
(a) The height of cliff A is (1) one-half, (2) two times, (3) four times that of cliff B.
(b) If it takes 1.80 s for the object to fall from cliff A to the water, what are the heights of cliffs A and B? |
doc |
| 55264 | The thickness of the numbered pages of a textbook is measured to be 3.75 cm.
(a) If the last page of the book is numbered 860, what is the average thickness of a page?
(b) Repeat the calculation by using order- of- magnitude calculations. |
doc |
| 55265 | The speed limit in a school zone is 40 km/h (about 25 mi/h). A driver traveling at this speed sees a child run onto the road 13 m ahead of his car. He applies the brakes, and the car decelerates at a uniform rate of 8.0 m/s2. If the driver’s reaction time is 0.25 s, will the car stop before hitting the child? |
doc |
| 55266 | The Roman Coliseum used to be flooded with water to re- create ancient naval battles. Assuming the circular floor be 250 m in diameter and the water to have a depth of 10 ft,
(a) how many cubic meters of water are required?
(b) How much mass would this water have in kilograms?
(c) How much would the water weigh in pounds? |
doc |
| 55267 | The Petron as Twin Towers in Malaysia and the Chicago Sears Tower have heights of about 452 m and 443 m, respectively. If objects were dropped from the top of each, what would be the difference in the time it takes the objects to reach the ground? |
doc |
| 55268 | The outside dimensions of a cylindrical soda can are reported as 12.559 cm for the diameter and 5.62 cm for the height.
(a) How many significant figures will the total outside area have: (1) two, (2) three, (3) four, or (4) five? Why?
(b) What is the total outside surface area of the can in square centimeters? |
doc |
| 55269 | The metric system is a decimal (base-10) system, and the British system is, in part, a duodecimal (base-12) system. Discuss the ramifications if our monetary system had a duodecimal base. What would be the possible values of our coins if this were the case? |
doc |
| 55270 | The mass of the Earth is 5.98 x 1024 kg. What is the average density of the Earth in standard units? |
doc |
| 55271 | The location of a moving particle at a particular time is given by x = at – bt2, where and a = 10 m/s and b = 0.50 m/s2.
(a) Where is the particle at t = 0?
(b) What is the particle’s displacement for the time interval t1 = 2.0s and t2 = 4.0s? |
doc |
| 55272 | The lightest solid material is silica aerogel, which has a typical density of only about .010 g/cm3. The molecular structure of silica aerogel is typically 95% empty space. What is the mass of 1 m3 of silica aerogel? |
doc |
| 55273 | The interior storage compartment of a restaurant refrigerator measures 1.3 m high, 1.05 m wide, and 67 cm deep. Determine its volume in cubic feet. |
doc |
| 55274 | The human heartbeat, as determined by the pulse rate, is normally about 60 beats/min. If the heart pumps 75 mL of blood per beat, what volume of blood is pumped in one day in liters? |
doc |
| 55275 | The general equation for a parabola is y = ax2 + bx + c, where a, b, and c are constants. What are the units of each constant if y and x are in meters? |
doc |
| 55276 | The driver of a pickup truck going 100 km/h applies the brakes, giving the truck a uniform deceleration of while it travels 20.0 m.
(a) What is the speed of the truck in kilometers per hour at the end of this distance?
(b) How much time has elapsed? |
doc |
| 55277 | The displacement of an object is given as a function of time by x = 3t2 m. What is the magnitude of the average velocity for
(a) ∆t = 2.0 s – 0s, and
(b) ∆t = 4.0 s – 2.0s? |
doc |
| 55278 | The density of metal mercury is 13.6 g/cm3.
(a) What is this density as expressed in kilograms per cubic meter?
(b) How many kilograms of mercury would be required to fill a 0.250- L container? |
doc |
| 55279 | The correct equation for the volume of a sphere is V = 4πr3/3, where r is the radius of the sphere. Is the equation in Exercise 12 correct? If not, what should it be when expressed in terms of d? |
doc |
| 55280 | The average number of hairs on the normal human scalp is 125 000. A healthy person loses about 65 hairs per day. (New hair from the hair follicle pushes the old hair out.)
(a) How many hairs are lost in one month?
(b) Pattern baldness (top-of-the-head hair loss) affects about 35 million men in the United States. If an average of 15% of the scalp is bald, how many hairs are lost per year by one of these “bald is beautiful” people? |
doc |
| 55281 | The angular momentum (L) of a particle of mass m moving at a constant speed v in a circle of radius r is given by L = mvr (Section 8.5).
(a) What are the units of angular momentum in terms of SI base units?
(b) The units of kinetic energy in terms of SI base units are kg∙m2 / s2. Using SI unit analysis, show that the expression for the kinetic energy of this particle in terms of its angular momentum, K = L2 / 2mr2’, is dimensionally correct.
(c) In the previous equation, the term mr2 is called the moment of inertia of the particle in the circle. What are the units of moment of inertia in terms of SI base units? |
doc |
| 55282 | The acceleration due to gravity on the Moon is about one-sixth of that on the Earth.
(a) If an object were dropped from the same height on the Moon and on the Earth, the time it would take to reach the surface on the Moon is (1) √6, (2) 6, or (3) 36 times the time it would take on the Earth.
(b) For a projectile with an initial velocity of upward, what would be the maxi-mum height and the total time of flight on the Moon and on the Earth? |
doc |