Answer:
B ) 1.5 m/s
Explanation:
For the apparent frequency reflected by enemy submarine , the Doppler effect formula is
F = F₀ ( V + v) / (V - v)
F anf F₀ are real and apparent frequency , V and v are velocity of sound and velocity of enemy submarine respectively.
ΔF / F₀ = 
Put ΔF = 200; F₀ = 100000 and V = 1482
200 / 100000 = 
v = 1.5 m s⁻¹ .
Porcine = of, affecting, or resembling a pig or pigs
Equine = of, relating, or affecting horses or other members of the horse family
Ursine = of, relating to, or resembling bears
Feline = Of, relating to, or affecting cats or other members of the cat family
Your answer is option "D. feline"
(definitions from "New Oxford American Dictionary)
Answer:
Positive
Explanation:
An ideal fluid is on which is incompressible and non-viscous.
In an ideal fluid element when a fluid element moves from a region of high pressure to region of low pressure then the work done on the fluid element is positive because the force acts in the direction from high pressure towards low pressure and displaces the fluid element, so the work-done is positive.
The total force applied by the three people is:

This force is pushing toward the direction of the motion, while the frictional force

points in the opposite direction.
We can write Newton's second law applied to the block: the resultant of the two forces must be equal to the product between the block's mass and its acceleration

We know the mass of the block, m=500 kg, and the acceleration,

, so we can find the friction: