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11111nata11111 [884]
3 years ago
15

"A boat that can travel at 4.0 km/h in still water crosses a river with a current of 2.0 km/h. At what angle must the boat be po

inted upstream (that is, relative to its actual path) to go straight across the river?

Physics
1 answer:
IRISSAK [1]3 years ago
8 0

Answer:

30 degrees

Explanation:

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Julie throws a ball to her friend Sarah. The ball leaves Julie's hand a distance 1.5 meters above the ground with an initial spe
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Answer:

Explanation:

1.  V_{x} = V_{0} * cos\alpha ⇒ 16*cos32 ≈ 13.6 m/s (13.56)

2. V_{y} = V_{0} * sin\alpha ⇒ 16* sin32 ≈ 9.4 m/s

3. y_{max} = \frac{v_{0}^2*sin^2\alpha}{2g}= \frac{16^2*sin^232}{2*9.8} (the g (gravity) depends on the country but i'll take the average g which is 9.2m/s^2)

y_{max} ≈ 3.6677+1.5 ≈ 5.2m

4.  x_{max} = \frac{v_{0}^2*sin(2\alpha)}{g}=\frac{16^2*sin(2*32)}{9.8} ≈ 23.5m (23.47)

5. -

answer 4 could be wrong, not certain about that one and i don't know 5

3 0
3 years ago
The electrical conductivity of a substance depends on the ability of the ____ in it to move. A) electrons B) neutrons C) protons
musickatia [10]

The correct answer to the question is A) Electrons.

EXPLANATION:

The electrical conductivity of a metal or any substance depends on the free electron concentration of the metals.

Free electrons are those electrons which are present in the conduction band of the metals. These electrons experience less amount of force attraction from the nucleus. Protons and neutrons do not  contribute anything to the current conduction in a metal.These sub atomic particles are bound to the nuclei of atoms.

When we maintain potential difference across the two ends of a conductor, the free electrons are drifted towards the positive terminal of the battery.

Hence, electrical conductivity of a substance is the ability of the electrons to move inside the substance.

More is the conductivity of the substance, the lesser is the resistance to the flow of electrons inside the substance, and vice versa.

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3 years ago
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Suppose a scientist doing an experiment in nuclear fusion starts out with twelve atoms. How many atoms will most likely result f
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<span>So we wan't to know what happens during nuclear fusion where we have 12 atoms. Nuclear fusion is a nuclear process where 2 or more nuclei will form 1 or more different nuclei with a release of energy. So if we start with 12 atoms, the most likely result will be 6 atoms. </span>
3 0
3 years ago
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A block of mass 10 kg and measuring 250 mm on each edge is pulled up an inclined surface on which there is a film of SAE 10W-30
Ivan

Answer:

a) 2.53 * 10^-2 m/s

b) -4.78 * 10^-2 m/s

c)  1.21 * 10^-1 m/s

Explanation:

Given data :

Mass of block = 10 kg

Measuring 250mm on each side

a) calculate the speed  when a force of 75N is applied to pull block upwards

F = f + W sin∅ ( equation for applying the force of equilibrium condition in the x axis )  ----- ( 1 )

f ( friction force )=  ( 16400v * 6.25 *10^-2) =  1025 v

F ( force applied ) = 75

W ( weight of  block ) = 10 * 9.81 = 98.1 N

∅ = 30°

input values into equation 1

V = \frac{75- (98.1*sin30^{0}) }{1025} = 2.53 * 10^-2 m/s

b) Speed when no force is applied on the block

F = f + W sin∅

F = 0

f = 1025 V

W = 98.1 N

∅ = 30°

hence V = \frac{0 - (98.1*sin30^{0}) }{1025} =  - 4.78 * 10^-2 m/s

c) when a force is applied to push block down the incline

F = f + W sin∅ ----- ( 3 )

F = 75 N

f = 1025 V

W = 98.1 N

∅ = 30°

input values into equation 3 considering the fact that the weight of the block is acting in the opposite direction

75 = 1025 V - 98.1 ( sin 30° )

V = \frac{75+( 98.1*sin30^{0})  }{1025} = 1.21 * 10^-1 m/s

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3 years ago
How was son I Ali able to create such a wealthy kingdom
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He was a good king and his subjects liked him. My name is Ali too. Plz 5 star give thx and brainliest

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