Assuming that the entirety of the force is opposite the static friction, then the couch should begin sliding as the applied force overcomes the couch's static friction with what it's making contact with.
Angle made by the light ray with the surface of mirror is given as
degree
now as we know as per law of reflection that
angle of incidence = angle of reflection
So here we can say that


now the total angle that reflected ray will rotate with respect to incident ray is known as angle of deviation


so here reflected light will deviate by total angle of 40 degree fron its incident ray.
Answer:
Explanation:
1 ) the volume of helium in the balloon when fully inflated
= 4/3 π R³
= 4/3 x 3.14 x 5.3³
= 623.3 m³
2 ) force of gravity on the entire system ,but with no people
= (mass of the empty balloon and basket + mass of helium )x g
=( 129 + 623.3 x.18 )x 9.8
= 2363.7 N
3 ) magnitude of the buoyant force on the entire system (but with no people )
( Volume of empty balloon + basket + volume of helium ) density of air x g
( 0.057 + 623.3 ) x 1.23 x 9.8
= 7513.94 N
4 ) magnitude of the force of gravity on each person
Mass of each person x g
= 71 x 9.8
= 695.8 N