Answer:
I think (d) is right answer
Answer:

Explanation:
Given:
- relativistic length of stick A,

- relativistic velocity of stick A with respect to observer,

<em>Since the object is moving with a velocity comparable to the velocity of light with respect to the observer therefore the length will appear shorter according to the theory of relativity.</em>
<u> Mathematical expression of the theory of relativity for length contraction:</u>

where:
L = relativistic length
original length at rest
Lorentz factor 



m = mass held by mr. Z above his head = 200 kg
g = acceleration due to gravity = 9.8 m/s²
F = force applied by mr. Z to hold the mass
Using equilibrium of force , force equation is given as
F = mg
F = (200) (9.8)
F = 1960 N
Since the mass is not moved,
d = displacement of the mass = 0 m
we know that , work done is given as
W = F d
inserting the values
W = (1960) (0)
W = 0 J
1.49 MPH (Miles Per Hour)
Answer:
Th-234, Pa-234
Explanation:
In alpha decay, 2 protons and 2 neutrons are lost. So U-238 would become Th-234.
In beta decay, one neutron is turned into a proton. So Th-234 would become Pa-234.