An observer O notes a particle moving to the right with velocity v . Another obs
ID: 1649460 • Letter: A
Question
An observer O notes a particle moving to the right with velocity v. Another observer O is moving with speed v relative to O along the direction of the motion of the particle. Which of the following is the value of the particle’s mass as measured by O and O?
Select one:
a. O and O' both measure m0
b. O and O' both measure m
c. O measures m0 and O' measures m
d. O measures m and O' measures m0
The main pipe coming into a factory is 8 m in diameter, and the water in that pipe enters the building at 1 m/s. Once inside, however, the pipe divides into four pipes that are each 4 m in diameter. Which of the following is the velocity of the water in the smaller pipes?
Select one:
a. 2 m/s
b. 4 m/s
c. 0.25 m/s
d. The velocity in the smaller pipes is the same as the velocity in the larger pipe.
Explanation / Answer
Observer O measures the original mass of the particle and O' measures the mass of the particle with respect to relative velocity
hence the answer is
c) O measures mo and O' measures m
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using eqution of continuty
A1*v1 = A2*v2
pi*(8/2)^2*1 = pi*(4/2)^2*v2
16 = 4*v2
v2 = 4 m/sec
so the correct answer is b) 4 m/sec