Answer:
According to Newton's 2nd law
The force acting on a body produces acceleration in its direction which is directly propotional to the force but inversly propotinal to the mass of tbe body.
Explanation:
a = F/m
F = ma
Where( F) is force (m) is mass and (a) is acceleration.
I believe the last one about the bike is correct.
Answer:
and
Explanation:
See attached figure.
E due to sphere
E due to particule
(1)
according to the law of gauss and superposition Law:
; electric field due to the small sphere with r1=R/4
then: 
(2)
on the other hand, for the particule:
⇒ 
(3)
We replace (2) y (3) in (1):
--------------------
if R<x<2R AND
remember that
then:
solving:
but: R<x<2R
so :
The correct answer is A. Most reactive non metals.
Firstly if some one knows how to read the periodic table he would have no confusion in deciding whether group 7 has metals or non metals. Group 7 contains non metals so basically we can easily cancel out two options of metals.
Secondly group 7 non metals are the most reactive non metals as they need only one electron in order to complete their valence shell and become stable.
