1. Using dimensions, convert 1 newton into dynes.
A.
10 dynes
B.
100 dynes
C.
1000 dynes
D.
100000 dynes
Correct Answer:
100000 dynes
Explanation:
Since 1 N = 1 kg m s^-2, and 1 kg = 1000 g and 1 m = 100 cm, 1 N = 1000 × 100 g cm s^-2 = 100000 dynes.
2. Using dimensions, 1 joule is equal to how many ergs?
A.
10^3 ergs
B.
10^5 ergs
C.
10^7 ergs
D.
10^9 ergs
Correct Answer:
10^7 ergs
Explanation:
A joule has dimensions kg m^2 s^-2. Converting kg to g and m^2 to cm^2 gives 1 J = 1000 × 10000 g cm^2 s^-2 = 10^7 ergs.
3. Convert 1 pascal into dynes per square centimetre.
A.
0.1 dyn cm^-2
B.
1 dyn cm^-2
C.
10 dyn cm^-2
D.
100 dyn cm^-2
Correct Answer:
10 dyn cm^-2
Explanation:
Pressure has dimensions force per area. Since 1 N = 10^5 dynes and 1 m^2 = 10^4 cm^2, 1 Pa = 10^5/10^4 = 10 dyn cm^-2.
4. A speed of 72 km h^-1 is equal to:
A.
2 m s^-1
B.
10 m s^-1
C.
20 m s^-1
D.
72 m s^-1
Correct Answer:
20 m s^-1
Explanation:
Speed has dimensions length per time. Thus, 72 km h^-1 = 72 × 1000/3600 m s^-1 = 20 m s^-1.
5. A density of 1 g cm^-3 is equal to:
A.
1 kg m^-3
B.
10 kg m^-3
C.
100 kg m^-3
D.
1000 kg m^-3
Correct Answer:
1000 kg m^-3
Explanation:
Density has dimensions mass per volume. Since 1 g = 10^-3 kg and 1 cm^3 = 10^-6 m^3, 1 g cm^-3 = 10^-3/10^-6 = 1000 kg m^-3.
6. Convert 1 watt into ergs per second.
A.
10^5 erg s^-1
B.
10^6 erg s^-1
C.
10^7 erg s^-1
D.
10^8 erg s^-1
Correct Answer:
10^7 erg s^-1
Explanation:
Power has dimensions energy per time. Since 1 joule = 10^7 ergs, 1 watt = 1 joule per second = 10^7 erg s^-1.
7. Using unit conversion for area, 1 cm^2 is equal to:
A.
10^-2 m^2
B.
10^-3 m^2
C.
10^-4 m^2
D.
10^-6 m^2
Correct Answer:
10^-4 m^2
Explanation:
Since 1 cm = 10^-2 m, squaring both sides gives 1 cm^2 = (10^-2 m)^2 = 10^-4 m^2.
8. A velocity of 1 m s^-1 is equal to:
A.
1 cm s^-1
B.
10 cm s^-1
C.
100 cm s^-1
D.
1000 cm s^-1
Correct Answer:
100 cm s^-1
Explanation:
Velocity has dimensions length per time. Since 1 m = 100 cm, 1 m s^-1 = 100 cm s^-1.
9. Using dimensional conversion, 1 m^3 is equal to:
A.
10^2 cm^3
B.
10^4 cm^3
C.
10^6 cm^3
D.
10^9 cm^3
Correct Answer:
10^6 cm^3
Explanation:
Since 1 m = 100 cm, cubing both sides gives 1 m^3 = (100 cm)^3 = 10^6 cm^3.
10. Convert an acceleration of 1 m s^-2 into cm s^-2.
A.
1 cm s^-2
B.
10 cm s^-2
C.
100 cm s^-2
D.
1000 cm s^-2
Correct Answer:
100 cm s^-2
Explanation:
Acceleration has dimensions length per time squared. Since 1 m = 100 cm and the time unit remains unchanged, 1 m s^-2 = 100 cm s^-2.
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