A boat can travel in still water at 56 m/s. If the boats sails directly across a river that flows at 126 m/s. What is the boats speed relative to the ground

Answers

Answer 1
Answer:

Answer:

The answer is below

Explanation:

The speed of the boat in still water is perpendicular to the speed of the water flow. Therefore the speed relative to the ground (V), the speed of flow and the speed of the boat in still water form a right angled triangle. Hence the speed relative to the ground is given as:

V² = 56² + 126²

V² = 19012

V = 137.9 m/s


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Water flows at speed of 4.4 m/s through ahorizontal pipe of diameter 3.3 cm . The gauge
pressure P1 of the water in the pipe is 2 atm .
A short segment of the pipe is constricted to
a smaller diameter of 2.4 cm
(IMAGE)
What is the gauge pressure of the water
flowing through the constricted segment? Atmospheric pressure is 1.013 × 10^5 Pa . The density of water is 1000 kg/m^3
. The viscosity
of water is negligible.
Answer in units of atm

Answers

Answer:

1.75 atm

Explanation:

Mass is conserved, so the mass flow before the constriction equals the mass flow after the constriction.

m₁ = m₂

ρQ₁ = ρQ₂

Q₁ = Q₂

v₁A₁ = v₂A₂

v₁ πd₁²/4 = v₂ πd₂²/4

v₁ d₁² = v₂ d₂²

Now use Bernoulli equation:

P₁ + ½ ρ v₁² + ρgh₁ = P₂ + ½ ρ v₂² + ρgh₂

Since h₁ = h₂:

P₁ + ½ ρ v₁² = P₂ + ½ ρ v₂²

Writing v₂ in terms of v₁:

P₁ + ½ ρ v₁² = P₂ + ½ ρ (v₁ d₁²/d₂²)²

P₁ + ½ ρ v₁² = P₂ + ½ ρ v₁² (d₁/d₂)⁴

P₁ + ½ ρ v₁² (1 − (d₁/d₂)⁴) = P₂

Plugging in values:

P₂ = 2 atm + ½ (1000 kg/m³) (4.4 m/s)² (1 − (3.3 cm / 2.4 cm)⁴) (1 atm / 1.013×10⁵ Pa)

P₂ = 1.75 atm

The deepest point of the Pacific Ocean is 11,033 m, in the Mariana Trench. What is the water pressure at that point? The density of seawater is 1025 kg/m3. The deepest point of the Pacific Ocean is 11,033 m, in the Mariana Trench. What is the water pressure at that point? The density of seawater is 1025 kg/m3. 1.11 × 104 Pa 1.09 × 105 Pa 1.13 × 107 Pa 1.11 × 108 Pa 2.18 × 105 Pa

Answers

Answer: 1.11 x 10⁸ Pa

Explanation:

At any deep, the absolute pressure is the same for all points located  at the same level, and can be expressed as follows:

p = p₀ + δ. g . h, where p₀ = atmospheric pressure = 101, 325 Pa

Replacing by the values, we get:

p= 101,325 Pa + 1025 Kg/m³ . 9.8 m/s². 11,033 m = 1.11 x 10⁸ Pa.

A river 500 ft wide flows with a speed of 8 ft/s with respect to the earth. A woman swims with a speed of 4 ft/s with respect to the water.1) If the woman heads directly across the river, how far downstream is she swept when she reaches the opposite bank?
2) If she wants to be swept a smaller distance downstream, she heads a bit upstream. Suppose she orients her body in the water at an angle of 37° upstream (where 0° means heading straight accross, how far downstream is she swept before reaching the opposite bank?
3) For the conditions, how long does it take for her to reach the opposite bank?

Answers

Answer:

1) \Delta s=1000\ ft

2)  \Delta s'=998.11\ ft.s^(-1)

3) t\approx125\ s

t'\approx463.733\ s

Explanation:

Given:

width of river, w=500\ ft

speed of stream with respect to the ground, v_s=8\ ft.s^(-1)

speed of the swimmer with respect to water, v=4\ ft.s^(-1)

Now the resultant of the two velocities perpendicular to each other:

v_r=√(v^2+v_s^2)

v_r=√(4^2+8^2)

v_r=8.9442\ ft.s^(-1)

Now the angle of the resultant velocity form the vertical:

\tan\beta=(v_s)/(v)

\tan\beta=(8)/(4)

\beta=63.43^(\circ)

  • Now the distance swam by the swimmer in this direction be d.

so,

d.\cos\beta=w

d* \cos\ 63.43=500

d=1118.034\ ft

Now the distance swept downward:

\Delta s=√(d^2-w^2)

\Delta s=√(1118.034^2-500^2)

\Delta s=1000\ ft

2)

On swimming 37° upstream:

The velocity component of stream cancelled by the swimmer:

v'=v.\cos37

v'=4* \cos37

v'=3.1945\ ft.s^(-1)

Now the net effective speed of stream sweeping the swimmer:

v_n=v_s-v'

v_n=8-3.1945

v_n=4.8055\ ft.s^(-1)

The  component of swimmer's velocity heading directly towards the opposite bank:

v'_r=v.\sin37

v'_r=4\sin37

v'_r=2.4073\ ft.s^(-1)

Now the angle of the resultant velocity of the swimmer from the normal to the stream:

\tan\phi=(v_n)/(v'_r)

\tan\phi=(4.8055)/(2.4073)

\phi=63.39^(\circ)

  • Now let the distance swam in this direction be d'.

d'* \cos\phi=w

d'=(500)/(\cos63.39)

d'=1116.344\ ft

Now the distance swept downstream:

\Delta s'=√(d'^2-w^2)

\Delta s'=√(1116.344^2-500^2)

\Delta s'=998.11\ ft.s^(-1)

3)

Time taken in crossing the rive in case 1:

t=(d)/(v_r)

t=(1118.034)/(8.9442)

t\approx125\ s

Time taken in crossing the rive in case 2:

t'=(d')/(v'_r)

t'=(1116.344)/(2.4073)

t'\approx463.733\ s

Hearing the siren of an approaching fire truck, you pull over to side of the road and stop. As the truck approaches, you hear a tone of 460 Hz; as the truck recedes, you hear a tone of 410 Hz. How much time will it take to jet from your position to the fire 5.00 km away, assuming it maintains a constant speed?

Answers

Answer:

The truck will reach there in 250 seconds.

Explanation:

The frequency due to doppler effect, when the observer is stationary and the source is moving towards it is

f_(obv)=(v)/(v-v_(s) ) f

where v= velocity of sound in air

v_(s)= velocity of source of sound

f= frequency of sound and

f_(obv)= frequency oberved due to Doppler effect

(v)/(v-v_(0) ) f = 460------------------------------------------( 1 )

The frequency due to doppler effect, when the observer is stationary and the source is moving away from it

f_(obv)=(v)/(v+v_(s) ) f

where v= velocity of sound in air

v_(s)= velocity of source of sound

f= frequency of sound and

f_(obv)= frequency oberved due to Doppler effect

(v)/(v+v_(0) ) f = 410-------------------------------------------( 2 )

Dividing ( 1 ) by ( 2 )

(v+v_(s) )/(v-v_(s) ) =(460)/(410)

(v+v_(s) )/(v-v_(s) ) =(46)/(41)

41v + 41v_(s) = 46v  - 46v_(s)

87v_(s)= 5v

v_(s)=(5)/(87)v

Velocity of Sound (v)= 348 m/s

v_(s)=20 m/s

Therefore, the truck is moving at 20 m/s.

Time=(Distance)/(Time)

Distance= 5000 m

Time=(5000)/(20)

Time= 250 s

Time = 4 min 10 sec          

         

         

         

         

What is the force (in Newtons, 1 Newton = 1Kgm/s2) required to accelerate a 1500 Kg car to 3 m/s2?

Answers

Answer:

F=4500N

Explanation:

F=m×g

F=1500kg×3m/s²

F=4500N

Answer:

F=4500N

Explanation:

F=m×g

F=1500kg×3m/s²

F=4500N

The height h (in feet) of an object shot into the air from a tall building is given by the function h(t) = 650 + 80t − 16t2, where t is the time elapsed in seconds. (a) Write a formula for the velocity of the object as a function of time t.

Answers

Answer:

80 - 32t

Explanation:

The height, h, in terms of time, t, is given as:

h(t) = 650 + 80t − 16t²

Velocity is the derivative of distance with respect to time:

v(t) = dh(t)/dt = 80 - 32t

Final answer:

The velocity of the object as a function of time is given by the derivative of the height function, which is v(t) = 80 - 32t.

Explanation:

The height h(t) of an object is given by the equation h(t) = 650 + 80t − 16t2. To find the velocity v(t), we need to take the derivative of h(t) with respect to time t. Using the power rule, we get:

v(t) = dh/dt = 0 + 80 - 32t.

So, the velocity of the object as a function of time t is v(t) = 80 - 32t.

Learn more about Velocity Function here:

brainly.com/question/33157131

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