A motorboat maintained a constant speed of 15 miles per hour relative to the water in going 10 miles upstream and then returning
1 answer:
Answer:
speed of current is 5 mile/hr
Explanation:
GIVEN DATA:
speed of motorboat = 15 miles/hr relative with water
let c is speed of current
15-c is speed of boat at upstream
15+c is speed of boat at downstream
we know that
travel time=distance/speed
150+10c+150-10c=1.5(15-c)(15+c)
300=1.5(225-c^2)
300=337.5-1.5c^2
200=225-c^2
c^2=25
c = 5
so speed of current is 5 mile/hr
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Answer:
The hollow cylinder rolled up the inclined plane by 1.91 m
Explanation:
From the principle of conservation of mechanical energy, total kinetic energy = total potential energy
The total energy at the bottom of the inclined plane = total energy at the top of the inclined plane.
moment of inertia, I, of a hollow cylinder = ¹/₂mr²
substitute for I in the equation above;
given;
v₁ = 5.0 m/s
vf = 0
g = 9.8 m/s²
Therefore, the hollow cylinder rolled up the inclined plane by 1.91 m