14-needle heading west
15-the strength of the current and the distance
Answer:
D
Explanation:
because it is the only one that has something to do with heat keyword would be boiling
Answer:
the time needed for her to close the door is 1.36 s.
Explanation:
given information:
Force, F = 220 N
width, r = 1.40 m
weight, W = 790 N
height, h = 3.00 m
angle, θ = 90° = π/2
to find the times needed to close the door we can use the following equation
θ = ω₀t + 1/2 αt²
where
θ = angle
ω = angular velocity
α = angular acceleration
t = time
in this case, the angular velocity is zero. thus,
θ = 1/2 αt²
now, we can find the angular speed by using the torque formula
τ = I α
where
τ = torque
I = Inertia
we know that
τ = F r
and
I = 1/3 mr²
so,
τ = I α
F r = 1/3 mr² α
α = 3 F/mr
= 3 F/(w/g)r
= 3 (220)/(790/9.8) 1.4
= 5.85 rad/s²
θ = 1/2 αt²
π/2 = 1/2 5.85 t²
t = 1.36 s
