Phys101
Term: 122
Online HW-Ch01-Lec01
Q1:
Which of the following have the same dimension?
1)
2)
3)
4)
5)
5 milliseconds.
3 seconds.
15 kilograms.
7 grams.
2 seconds.
A)
B)
C)
D)
E)
1 and 3.
2, 3 and 4.
2, 3 and 5.
1, 2, and 4.
1, 2, and 5
Ans:
𝐄
Q2:
Convert the sum of 6 hours, 20 minutes and 15 seconds into seconds. (Give your
answer in three significant figures form)
Ans:
3600 s
60 s
6 hrs + 20 min + 155 = (6 hr) �
� + 20 min �
� + 15 s
1 hr
1 min
= 22815 ≅ 228 × 102 s
Q3:
Suppose A = t.Bn.C, where A has dimensions LT, B has dimensions T/L, C has
dimensions T3/L2 and t is time. Find the value of the exponent n. (Give your answer in
three significant figures form)
Ans:
[A] = LT; [t] = T ; [B] =
T n T3
LT = T. � � . � 2 �
L
L
T
T3
; [C] = 2
L
L
T. T n . T 3
⇒ LT =
= T1+n+3 . L−n−2
n
2
L .L
The exponent of T on the left hand side is equal to the exponent of T on the right-hand
side (same for L)
1 = 1 + n + 3 ⇒ n = − 3.00
KFUPM-Physics Department
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