Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
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Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics Test Bank by Wolfson 3rd Edition
Essential University Physics, 3e (Wolfson) Chapter 8 Gravity
8 . 1 Conc e p t ua lQue s t i o ns 1) A baseball is located at the surface of the earth. Which statements about it are correct? (There may be more than one correct choice.) A) The earth exerts a much greater gravitational force on the ball than the ball exerts on the earth. B) The ball exerts a greater gravitational force on the earth than the earth exerts on the ball. C) The gravitational force on the ball due to the earth is exactly the same as the gravitational force on the earth due to the ball. ) The gravitational force on the ball is inde!endent of the mass of the ball. ") The gravitational force on the ball is inde!endent of the mass of the earth. Ans#er$ C %ar$ 1
&) A very small round ball b all is located near a large solid s!here of uniform density. The The force that the large s!here exerts on the ball A) is exactly the same as it #ould be b e if all the mass of the s!here #ere concentrated at the center of the s!here. B) is a!!roximately the same as it #ould be if all the mass of the s!here #ere concentrated co ncentrated at the center of the s!here. C) is inde!endent of the mass of the ball. ) is inde!endent of the mass of the s!here. ") can only be calculated using calculus. Ans#er$ A %ar$ 1
') lanet *'+ has a mass e,ual e,ua l to 1-' that of "arth a radius e,ual e, ual to 1-' that of "arth and an d an axial s!in rate 1-& that of "arth. With g With g re!resenting re!resenting as usual the acceleration due to gravity on the surface of "arth the acceleration due to gravity on the surface of *'+ is A) g A) g -'. -'. B) ' g. C) / g . ) g ) g -0. -0. ") 0 g. Ans#er$ B %ar$ 1
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+) 3f the mass of the earth and all ob4ects on it #ere suddenly doubled but the si5e remained the same the acceleration due to gravity at the surface #ould become A) + times #hat it no# is. B) & times #hat it no# is. C) the same as it no# is. ) 1-& of #hat it no# is. ") 1-+ of #hat it no# is. Ans#er$ B %ar$ 1
6) T#o !lanets having e,ual masses are in circular orbit around a star. lanet A has a smaller orbital radius than !lanet B. Which statement is true? A) lanet A has more 7inetic energy less !otential energy and less mechanical energy (!otential !lus 7inetic) than !lanet B. B) lanet A has more 7inetic energy more !otential energy and more mechanical energy (!otential !lus 7inetic) than !lanet B. C) lanet A has more 7inetic energy less !otential energy and more mechanical energy (!otential !lus 7inetic) than !lanet B. ) lanet A and !lanet B have the same amount of mechanical energy (!otential !lus 7inetic). Ans#er$ A %ar$ 1
/) A certain !lanet has an esca!e s!eed V . 3f another !lanet of the same si5e has t#ice the mass as the first !lanet its esca!e s!eed #ill be A) &V. B) V. C) V . ) V -&. ") V/ . Ans#er$ B %ar$ 1
8) A certain !lanet has an esca!e s!eed V . 3f another !lanet has t#ice si5e and t#ice the mass of the first !lanet its esca!e s!eed #ill be A) &V. B) V. C) V . ) V -&. ") V/ . Ans#er$ C %ar$ 1
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9) A satellite is orbiting the earth. 3f a !ayload of material is added until it doubles the satellite:s mass the earth:s !ull of gravity on this satellite #ill double but the satellite:s orbit #ill not be affected. A) True B) ;alse Ans#er$ A %ar$ 1
0) A satellite in a circular orbit of radius R around !lanet X has an orbital !eriod T . 3f lanet X had one*fourth as much mass the orbital !eriod of this satellite in an orbit of the same radius #ould be A) +T. B) &T. C) T ) T -&. ") T -+. Ans#er$ B %ar$ 1
12) A satellite of mass m has an orbital !eriod T #hen it is in a circular orbit of radius R around the earth. 3f the satellite instead had mass +m its orbital !eriod #ould be A) +T. B) &T. C) T. ) T -&. ") T -+. Ans#er$ C %ar$ 1
11) The reason an astronaut in an earth satellite feels #eightless is that A) the astronaut is beyond the range of the earth:s gravity. B) the astronaut is falling. C) the astronaut is at a !oint in s!ace #here the effects of the moon:s gravity and the earth:s gravity cancel. ) this is a !sychological effect associated #ith ra!id motion. ") the astronaut:s acceleration is 5ero. Ans#er$ B %ar$ 1
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8 . 2 Pr o bl e ms 1) A small*si5ed 166*7g mass is located 1.62 m from a small*si5ed &86*7g mass #ith both masses fixed in !lace. Where should you !lace a third small*si5ed mass so that the net gravitational force on it due to the original t#o masses is 5ero? Ans#er$ 2./+' m from the 166*7g mass along the line connecting the t#o given masses %ar$ 1
&) An astronaut is in e,uilibrium #hen he is !ositioned from the center of asteroid X and from the center of asteroid Y along the straight line 4oining the centers of the asteroids. What is the ratio of the masses X/Y of the asteroids? A) 2.2691 B) 18.& C) 2.&+1 ) +.16 Ans#er$ A %ar$ 62<
') Three identical very small 62*7g masses are held at the corners of an e,uilateral triangle 2.'2 m on each side. 3f one of the masses is released #hat is its initial acceleration if the only forces acting on it are the gravitational forces due to the other t#o masses? (G = /./8 > 12*11 @ m&-7g&) A) '.8 > 12*9 m-s& B) &.6 > 12*9 m-s& C) 1.0 > 12*9 m-s& ) +.& > 12*9 m-s& ") /.+ > 12*9 m-s& Ans#er$ " %ar$ 1
+) A small !lanet having a radius of 1222 7m exerts a gravitational force of 122 on an ob4ect that is 622 7m above its surface. 3f this ob4ect is moved 622 7m farther from the !lanet the gravitational force on it #ill be closest to A) 86 . B) 81 . C) 6/ . ) 62 . ") &6 . Ans#er$ C %ar$ 1
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6) The gravitational acceleration on a !lanet:s surface is 1 /.2 m-s&. What is the gravitational acceleration at an altitude of one !lanet diameter above the ;AC" of the !lanet? A) 6.'' m-s& B) 1.89 m-s& C) 1./2 m-s& ) +.22 m-s& ") 9.22 m-s& Ans#er$ B %ar$ 1
/) The radius of the earth is R. At #hat distance above the earth:s surface #ill the acceleration of gravity be +.0 m-s&? A) 2.+1 R B) 2.62 R C) 1.2 R ) 1.+ R ") &.2 R Ans#er$ A %ar$ 1
8) By ho# many ne#tons does the #eight of a 122*7g !erson change #hen he goes from sea level to an altitude of 6.2 7m if #e neglect the earth:s rotational effects? (The mean radius of the "arth is /.'9 > 12/ m G = /./8 > 12*11 @ m&-7g&.) A) *2./2 B) *1.6 C) *&./ ) *'./ ") *6.& Ans#er$ B %ar$ 1
9) The #eight of s!aceman !eff at the surface of !lanet X solely due to its gravitational !ull is '90 . 3f he moves to a distance of 1.9/ × 12+ 7m above the !lanet:s surface his #eight changes to &+.'1 . What is the mass of !lanet X if !eff:s mass is 86.2 7g? (G = /./8 > 12*11 @ m&-7g&) A) &.00 × 12&+ 7g B) &.00 × 1219 7g C) &.00 × 1218 7g ) 1.60 × 1219 7g Ans#er$ A %ar$ 1
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0) ;rom #hat height above the surface of the earth should an ob4ect be dro!!ed to initially ex!erience an acceleration of 2.0&22 g ? The radius of the earth is /.'9 > 12 / m. A) &8& 7m B) &/2 7m C) 66+ 7m ) 612 7m Ans#er$ A %ar$ 1
12) An ob4ect dro!s a distance h in a time of /.' s on the surface of the earth (neglecting air effects). Do# long #ould it ta7e the same ob4ect to dro! the same distance on the surface of s!herical asteroid X having a mass of 1.1 > 12&& 7g and a radius of +.2 > 126 m? (G = /./8 > 12* 11 @ m&-7g& M earth = 6.08 > 12&+ 7g Rearth = /.'9 > 12/ m) A) 0.& s B) /.' s C) 6.& s ) 1& s ") '.' s Ans#er$ A %ar$ 1
11) "7a!luto is an un7no#n !lanet that has t#o s!herical moons in circular orbits. The table summari5es the hy!othetical data about the moons. Both moons have lo# axial s!in rates. (G = /./8 > 12*11 @ m&-7g&)
Radius
Eoon A
Mass +.2 > 12&2 7g
Orbital radius &.2 > 129 m
Moon B
1.6 > 12&2 7g
&.2 > 126 m
'.2 > 129 m
The acceleration due to gravity at the surface of Eoon B is A) 2.12 m-s&. B) 2.16 m-s&. C) 2.&2 m-s&. ) 2.&6 m-s&. ") 2.'2 m-s&. Ans#er$ %ar$ 1
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Orbital period +.2 > 12/ s
1&) Sputni ! #as launched into orbit around "arth in 1068. 3t had a !erigee (the closest a!!roach to "arth measured from "arth:s center) of /.91 > 12/ m and an a!ogee (the furthest !oint from "arth:s center) of 8.6' > 12/ m. What #as its s!eed #hen it #as at its !erigee? The mass of "arth is 6.08 > 12&+ 7g and G = /./8 > 12*11 @ m&-7g&. A) 8192 m-s B) 89+2 m-s C) 9&'2 m-s ) 11222 m-s ") 1'+22 m-s Ans#er$ B %ar$ 1
1') Beings on s!herical asteroid " have observed that a large roc7 is a!!roaching their asteroid in a collision course. At from the center of the asteroid the roc7 has a s!eed of and later at it has a s!eed of se energy conservation to find the mass of asteroid ". Fou can neglect any effects due to the !arent star of the asteroid. (G = /./8 > 12*11 @ m&-7g&) A) +.69& ×
7g
B) 0.1/+ ×
7g
C) /.11& ×
7g
) +.69& ×
7g
Ans#er$ A %ar$ 62<
1+) What is the ratio of the esca!e s!eed of a roc7et launched from sea level to the esca!e s!eed of one launched from Et. "verest (an altitude of 9.96 7m)? The radius of the earth is /.'9 > 12/ m. A) 1.2228 B) 1.221+ C) 1.2221 ) 2.009/ ") 2.000' Ans#er$ A %ar$ 1
16) A huge cannon is assembled on an airless !lanet having insignificant axial s!in. The !lanet has a radius of 6.22 > 12/ m and a mass of '.06 > 12&' 7g. The cannon fires a !ro4ectile straight u! at &222 m-s. An observation satellite orbits the !lanet at a height of 1222 7m. What is the !ro4ectile:s s!eed as it !asses the satellite? (G = /./8 > 12*11 @ m&-7g&) A) 1622 m-s B) 1'92 m-s C) 1/12 m-s ) 1&92 m-s Ans#er$ A %ar$ 62< 8 Co!yright &21/ earson "ducation 3nc.
1/) A meteoroid heading straight for "arth has a s!eed of 1+.9 7m-s relative to the center of "arth as it crosses our moon:s orbit a distance of ' .9+ > 129 m from the earth:s center. What is the meteroidGs s!eed as it hits the earth? Fou can neglect the effects of the moon "arthGs atmos!here and any motion of the earth. (G = /./8 > 12*11 @ m&-7g& M earth = 6.08 > 12&+ 7g) A) 19.6 7m-s B) &1.6 7m-s C) '&.+ 7m-s ) 98.' 7m-s Ans#er$ A %ar$ 1
18) A certain s!herical asteroid has a mass of '.6 > 121/ 7g and a radius of 9.9 7m. What is the minimum s!eed needed to esca!e from the surface of this asteroid? (G = /./8 > 12*11 @ m&-7g&) A) &' m-s B) 1/ m-s C) 6&2 m-s ) 8'2 m-s Ans#er$ A %ar$ 62<
19) A 012*7g ob4ect is released from rest at an altitude of 1&22 7m above the north !ole of the earth. 3f #e ignore atmos!heric friction #ith #hat s!eed does the ob4ect stri7e the surface of the earth? (G = /./8 > 12*11 @ m&-7g& M earth = 6.08 > 12&+ 7g the !olar radius of the earth is /'68 7m) A) +.6 7m-s B) &.& 7m-s C) &.8 7m-s ) '.& 7m-s ") +.9 7m-s Ans#er$ A %ar$ 1
10) A satellite is in circular orbit at an altitude of 1622 7m above the surface of a nonrotating !lanet #ith an orbital s!eed of 0.& 7m-s. The minimum s!eed needed to esca!e from the surface of the !lanet is 1+.0 7m-s and G = /./8 > 12*11 @ m&-7g&. The orbital !eriod of the satellite is closest to A) 8& min. B) /6 min. C) 69 min. ) 61 min. ") ++ min. Ans#er$ A %ar$ 62<
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&2) A satellite is in circular orbit at an altitude of &'22 7m above the surface of a nonrotating asteroid #ith an orbital s!eed of 6.0 7m-s. The minimum s!eed needed to esca!e from the surface of the asteroid is 1+./ 7m-s and G = /./8 > 12*11 @ m&-7g&. The mass of the asteroid is closest to A) 1.9 > 12&+ 7g. B) 9.0 > 12&' 7g. C) 1.' > 12&+ 7g. ) &.8 > 12&+ 7g. ") './ > 12&+ 7g. Ans#er$ A %ar$ 62<
&1) An astronaut is standing on the surface of a !lanetary satellite that has a radius of 1.8+ > 12/ m and a mass of 8.'6 > 12&& 7g. An ex!eriment is !lanned #here a !ro4ectile needs to be launched straight u! from the surface. What must be the minimum initial s!eed of the !ro4ectile so it #ill reach a height of &.66 > 12 / m above this satelliteGs surface? (G # /./8 > 12*11 @ m&-7g&) Ans#er$ 1.9' 7m-s %ar$ 1
&&) The 3nternational !ace tation is orbiting at an altitude of about '82 7m above the earth:s surface. The mass of the earth is 6.08 > 12&+ 7g the radius of the earth is /.'9 > 12/ m and G = /./8 > 12*11 @ m&-7g&. Assuming a circular orbit (a) #hat is the !eriod of the 3nternational !ace tation:s orbit? (b) #hat is the s!eed of the 3nternational !ace tation in its orbit? Ans#er$ (a) 6.6& > 12' s (b) 8./0 > 12' m-s %ar$ 1
&') A satellite that #eighs +022 on the launch!ad travels around the earthGs e,uator in a circular orbit #ith a !eriod of 1.//8 h. The earthGs mass is 6.08 > 12&+ 7g its e,uatorial radius is /.' > 12/ m and G # /./8 > 12*11 @ m&-7g&. (a) Calculate the magnitude of the earth:s gravitational force on the satellite. (b) etermine the altitude of the satellite above the "arth:s ;AC". Ans#er$ (a) '012 (b) 8.66 > 126 m %ar$ 1
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&+) What is the !eriod (in hours) of a satellite circling Ears 122 7m above the !lanet:s surface? The mass of Ears is /.+& > 12&' 7g its radius is '.+2 > 12 / m and G = /./8 > 12*11 @ m&-7g&. A) 1.86 h B) 1.&6 h C) 1.16 h ) 1.22 h ") 1.+6 h Ans#er$ A %ar$ 1
&6) Hu!iter com!letes one revolution about its o#n axis every 0.0& hours. What is the radius of the orbit re,uired for a satellite to revolve about Hu!iter #ith the same !eriod? Hu!iter has a mass of 1.02 > 12&8 7g and G = /./8 > 12*11 @ m&-7g&. A) 1.2+ > 128 m B) &.&/ > 120 m C) 1./2 > 129 m ) '.+1 > 129 m ") 8.+6 > 129 m Ans#er$ C %ar$ 1
&/) The moons of Ears hobos (;ear) and eimos (Terror) are very close to the !lanet com!ared to "arth:s Eoon. Their orbital radii are 0'89 7m and &'+60 7m res!ectively. What is the ratio of the orbital s!eed of hobos to that of eimos? A) 2.&6&9 B) 2.'009 C) 1.69& ) &.969 ") '.06/ Ans#er$ C %ar$ 1
&8) !aceman !eff orbits s!herical asteroid X #ith his s!aceshi!. To remain in a circular orbit at from the asteroidGs center he should maintain a s!eed of What is the mass of !lanet X ? (G = /./8 > 12*11 @ m&-7g&) A) +.2 × 1210 7g B) 6.1 × 1218 7g C) +.2 × 121/ 7g ) 6.1 × 121+ 7g Ans#er$ A %ar$ 62<
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&9) ;ind the orbital s!eed of an ice cube in the rings of aturn. The mass of aturn is 6./9 > 12&/ 7g and the rings have an average radius of 122222 7m. (G = /./8 > 12*11 @ m&-7g&) A) 10.6 7m-s B) &8.6 7m-s C) 1'.9 7m-s ) 1.06 7m-s Ans#er$ A %ar$ 1
&0) Fou are the science officer on a visit to a distant solar system. rior to landing on a !lanet you measure its diameter to be 1.9 × 128 m and its rotation !eriod to be &&.' hours. Fou have !reviously determined that the !lanet orbits 1.9 × 1211 m from its star #ith a !eriod of +2& earth days. Ince on the surface you find that the acceleration due to gravity is 60.8 m-s&. What are the mass of (a) the !lanet and (b) the star? (G = /./8 > 12*11 @ m&-7g&.) A) (a) 8.& 7g ×
7g (b) &.0 7g ×
7g
B) (a) 1.' 7g ×
7g (b) &.0 7g ×
7g
C) (a) 8.& 7g ×
7g (b) 1.8 7g ×
7g
) (a) 1.' 7g ×
7g (b) 1.8 7g ×
7g
Ans#er$ A %ar$ 62<
'2) u!!ose #e #ant a satellite to revolve around the earth 6 times a day. What should be the radius of its orbit? (The mass of the earth is 6.08 × 12&+ 7g G = /./8 > 12*11 @ m&-7g& and you can neglect the !resence of the moon.) A) 1.++ × 128 m B) 2./02 × 128 m C) 8.&& × 128 m ) &.11 × 128 m Ans#er$ A %ar$ 0
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'1) "7a!luto is an un7no#n !lanet that has t#o moons in circular orbits. The table summari5es the hy!othetical data about the moons. (G = /./8 > 12*11 @ m&-7g&) Radius
Eoon A
Mass +.2 > 12&2 7g
Orbital radius &.2 > 129 m
Moon B
1.6 > 12&2 7g
&.2 > 126 m
'.2 > 129 m
Orbital period +.2 > 12/ s
The mass of "7a!luto is closest to A) 1.2 × 12&& 7g. B) '.2 × 12&& 7g. C) 1.2 × 12&' 7g. ) '.2 × 12&' 7g. ") 1.2 × 12&+ 7g. Ans#er$ %ar$ 1
'&) A man*made satellite of mass /126 7g is in orbit around the earth ma7ing one revolution in +'2 minutes. What is the magnitude of the gravitational force ex erted on the satellite by the earth? (The mass of the earth is /.2 > 12 &+ 7g and G = /./8 > 12*11 @ m&-7g&) Ans#er$ &.6 > 12' %ar$ 62<
