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erica [24]
3 years ago
13

Bob can row 14 mph in still water. The total time to travel downstream and return upstream to the starting point is 4 hours. If

the total distance downstream and back is 42 miles, determine the speed of the river (current speed).
Physics
1 answer:
bija089 [108]3 years ago
7 0

Answer:

7 mph

Explanation:

Let the speed of river is c mph.

The effective downstream speed = 14 + c

The effective upstream speed = 14 - c

Total time = 4 hrs

Total distance = 42 miles

Time for upstream + time for downstream = 4 hrs

21 / (14 + c) + 21 / (14 - c) = 4

21 (14 - c + 14 + c) = 4 (196 - c^2)

21 x 28 = 4 (196 - c^2)

c^2 = 196 -147 = 49

c = 7 mph

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5 0
3 years ago
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lesya692 [45]

Answer:

John Dalton

Explanation:

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3 years ago
Read 2 more answers
A man pushes an 250-N crate at constant speed a distance of 30.0 m upward along a rough slope that makes an angle of 60° with th
mel-nik [20]

Answer:

6495.19 Joule

Explanation:

F = Weight of the crate = 250 N

d = Distance the cart is pushed = 30 m

θ = Angle of inclination = 60°

The weight of the crate will be resloved into two components

Fdsinθ and Fdcosθ

Work done by the force of gravity is

W = Fdsinθ

⇒W = 250×30×sin60

⇒W = 6495.19 Joule

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8 0
3 years ago
Jackie rides her bike to school every day and enjoys playing beach volleyball on weekends. She also helps with tasks around the
Alinara [238K]

Answer:

The correct answer is - C) Jackie may maintain healthy body fat levels.

Explanation:

Jackie has a very active daily and on weekends routine that includes riding the bike, playing volleyball, pushing weeds, and sweeping the porch. The activities that Jackie is performing daily as well as the time that she spends on exercise may help her to maintain body fat levels.

Being physically active helps in maintaining fat levels in the body of an individual, and it is healthy for the individual.

Thus, the correct answer is - C) Jackie may maintain healthy body fat levels.

6 0
3 years ago
What type of resource is corn?
muminat
I believe Corn is a natural resource. It is a type of cereal plant grains, grown on Farms. 
7 0
3 years ago
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