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Crazy boy [7]
3 years ago
9

Determine the amount of work you would need to do in order to stop a 1100kg car with 1400J of kinetic energy.

Physics
1 answer:
LiRa [457]3 years ago
6 0

Answer:

 W = -1400 J

Explanation:

Let's use the relationship between work and kinetic energy

           W = ΔK

             

kinetic energy is

            K = ½ m v²

therefore in this case

             K₀ = 1400 J

         

Thus

            W = 0 -1400

            W = -1400 J

The negative sign indicates that the work is done against the energy, that is, in the opposite direction to the movement

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An object is held at rest and allowed to drop How far does the object fall in 3.3 seconds?
IgorC [24]
After x seconds, an object will fall \frac{1}{2}at^2 where a is acceleration due to gravity and t is time

so when t=3.3
the distance it will fall is (\frac{1}{2})(9.8\frac{m}{s^2})(3.3m)^2=53.361m
it will fal 53.361 meters
6 0
3 years ago
A material you are testing conducts electricity but cannot be pulled into wires. It is most likely a _____.
notsponge [240]

Answer: The correct answer is "metalloid".

Explanation:

Metal is the material which can conduct electricity as it contains free electrons. It is good conductor of electricity. For example, copper, silver.

Metal can be drawn into wires. This property of material is called ductile.

Metal can be beaten into sheets. This property of material is called malleable.

Non metal is the material which cannot conduct electricity as it does not contain free electrons. They are poor conductor of electricity. For example, oxygen.

Metalloid: It has properties of both metals and non metal. It is electrical conductor. For example, semiconductor- silicon and germanium. But they cannot be pulled into wires.

Therefore, a material you are testing conducts electricity but cannot be pulled into wires. It is most likely a metalloid.

6 0
3 years ago
To aid in the prevention of tooth decay, it is recommended that drinking water contain 0.800 ppm fluoride, F−. How many grams of
Leviafan [203]

Answer:

2.23 × 10^6 g of F- must be added to the cylindrical reservoir in order to obtain a drinking water with a concentration of 0.8ppm of F-

Explanation:

Here are the steps of how to arrive at the answer:

The volume of a cylinder = ((pi)D²/4) × H

Where D = diameter of the cylindrical reservoir = 2.02 × 10^2m

H = Height of the reservoir = 87.32m

Therefore volume of cylindrical reservoir = (3.142×202²/4)m² × 87.32m = 2798740.647m³

1ppm = 1g/m³

0.8ppm = 0.8 × 1g/m³

= 0.8g/m³

Therefore to obtain drinking water of concentration 0.8g/m³ in a reservoir of volume 2798740.647m³, F- of mass = 0.8g/m³ × 2798740.647m³ = 2.23 × 10^6 g must be added to the tank.

Thank you for reading.

4 0
3 years ago
A camera takes a properly exposed photo with a 4.0 mm diameter aperture and a shutter speed of 1/1000 s. If the photographer foc
hoa [83]

Answer:

option E

Explanation:

given,

diameter = 4 mm

shutter speed = 1/1000 s

diameter of aperture = ?

shutter speed = 1/250 s

exposure time to the shutter time

E V = log_2(\dfrac{N^2}{t})

N is the diameter of the aperture and t is the time of exposure

now,

log_2(\dfrac{N^2}{t_1})=log_2(\dfrac{N^2}{t_2})

\dfrac{N_1^2}{t_1}=\dfrac{N_2^2}{t_2}

inserting all the values

\dfrac{4^2}{1000}=\dfrac{N_2^2}{250}

      N₂² = 4

      N₂ = 2 mm

hence , the correct answer is option E

4 0
3 years ago
A river flows at 2m/s. The velocity of a ferry relative to the shore is 4m /s at right angle to the current. What is the velocit
monitta

The velocity of the ferry relative to the current is 4.5 m/s.

<h3>Relative velocity</h3>
  • Relative velocity is the velocity of a body as observed from the reference point of another body either stationary or in motion.

Since the river is flowing parallel to the shore and the ferry is moving perpendicular to the shore, their velocities are at right angles to each other.

The two velocities form a right angled-triangle of sides 2, 4 and a hypotenuse which gives the relative velocity of the ferry to the current.

Using Pythagoras rule:

  • c² = a² + b²
  • Let c be the hypotenuse
  • a =  velocity of the ferry, and
  • b = the velocity of the current, and

c² = 4² + 2²

c² = 16 + 4

c = 20

c = √20

c = 4.47 m/s

c ≈ 4.5 m/s

Therefore, the velocity of the ferry relative to the current is 4.5 m/s.

Learn more about relative velocity and Pythagoras rule at: brainly.com/question/25617868

5 0
2 years ago
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