According to Newton's 3rd law of motion, every action has an equal and opposite reaction.
So Wall must apply a force of 50 Newton but in opposite direction.
Hope you got it :-D
Answer:
140m east
Explanation:
If East is positive then lets rephrase the problem into integers
A truck moves +70 m, then moves -120m, and finally moves +90m.
So totally Displacement = +70-120+90= +140m
Since east is positive, the trucks resultant displacement is 140 m east of origin
Explanation:
It is given that The Moon's center is 3.9x10⁸ m from Earth's center. The moon 1.5x10⁸ km from the Sun's center. We need to find the ratio of the gravitational forces exerted by Earth and the Sun on the Moon.
The gravitational force is given by :

It means 
So,

r₁ = 3.9x10⁸ km
r₂= 1.5x10⁸ km
So,

Hence, the ratio of the gravitational forces exerted by Earth and the Sun on the Moon is 5:13.
The answer is D. the way I remember it is they all end with -alism.