Answer:
Speed, v = 5 m/s
Explanation:
The length of the football field, l = 100 m
the person takes 20 seconds to run its length
v=
t
d
v=
20 s
100 m
v=5 m/s
Answer:
B.Self powered
Explanation:
They move by themselves.Hope this answer helps you ;)
I definitly believe the answer is c. 2
Answer:
Relative and average atomic mass both describe properties of an element related to its different isotopes.
Explanation:However, relative atomic mass is a standardized number that's assumed to be correct under most circumstances, while average atomic mass is only true for a specific sample.
Answer: Beta particles cannot penetrate very far into solids because they <span><u>have no mass.
</u>
Reason<u>:
</u>Penetrating power of particle depending upon the velocity and mass of particle. Greater the mass and velocity. Higher will be the penetrating power. In case of Beta particles, they are electrons. Mass of an electron is 9.1 X </span>

Kg. Due to such negligible mass, they have very low penetrating power. <span /><span><u>
</u></span>