The unit for the speed was not given
If speed is 15km/h
and distance is 1.2km
Then using the formula
Speed = distance/time
Time = t
15 = 1.2/t
15t = 1.2
t = 1.2/15
t = 0.08hrs
But
1hr = 60seconds
0.08hrs = t
t = 60(0.08)
t = 4.8s
Proceed with caution before crossing
Answer:

Explanation:
given,
light is incident on the plane surface at (i) = 37°
angle of refraction (r) = ?
μ is the refractive index of the material
μ = 1.66
using Snell's law
hence. the angle of refraction is equal to 
Answer:
force exert horizontally is 1 N
Explanation:
given data
bar length = 3.7 m
mass = 4.5 kg
rope length = 6.7 m
to find out
force exert horizontally
solution
we know here bar length and rope length that make angle θ
so here cos θ = (3.7/6.7)
so equating the torque here to find force in horizontal direction is
Fx = T cos θ .........1
and in vertical direction
Tsinθ + N = mg .............2
so here
we consider equilibrium condition
so
Fx = 0
T cos θ = 0
T 3.7 / 6.7 = 0
T = 6.7/3.7
T = 1.81
so from equation 1
Fx = T cosθ
Fx = 1.81 ( 3.7/6.7)
Fx = 1 N
so force exert horizontally is 1 N