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3 years ago

A car traveling at 30m/s screeches to a halt, leaving 55 m long skid marks. what was the cars acceleration while braking

1 answer:

6 0

For this problem we use the derived equations for rectilinear motion at constant acceleration. The equation is written below:

2ax = v² - v₀²
where
a is the acceleration
x is the distance
v is the final velocity
v₀ is the initial velocity

Since the car comes to a stop eventually, v=0. Substituting the values,

2a(55) =0² - 30²
a = -8.18 m/s²

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what is the density of a substance that has a mass of 2.0 g , and when placed in a graduated cylinder the volume changed from 70

lubasha [3.4K]

A material with a mass of 2.0 g when placed in a graduated cylinder the volume changed from 70 ml to 75 ml has a density of 0.4 g/mL.

How do I calculate the substance's density?

We'll start by getting the substance's volume. This is attainable as follows:

Water volume: 70 mL

75 mL = volume of material + water.

Substance volume =?

Substance volume equals (substance volume plus water) - (Volume of water)

Substance volume = 75 - 70

5 mL is the substance's volume.

Finally, we will calculate the substance's density. Below is an example to help:

2.0 g is the substance's mass.

5 mL is the substance's volume.

Substance density =?

Mass / volume equals density.

Substance density = 2/5

0.4 g/mL is the substance's density.

The density is therefore 0.4 g/mL.

To know more about density, visit:

brainly.com/question/952755

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1 year ago

The force F shown in Figure 4.30 has a moment of 40 Nm about the pivot. Calculate the magnitude

salantis [7]

$\boxed{\sf \tau=rFsin\theta}$

Put values

$\\ \rm\hookrightarrow 40=2Fsin40$

$\\ \rm\hookrightarrow Fsin40=20$

$\\ \rm\hookrightarrow 0.64F=20$

$\\ \rm\hookrightarrow F=31.25N$

8 0

2 years ago

The gravitational force between two objects is represented by the variable F. If the distance is decreased by 5 what is the new

Anvisha [2.4K]

The universal law of gravitation states that:

Every object in the universe attracts every other object with a force which is proportional to the product of their masses and inversely proportional to the square of distance between them.

It means that if the gravitational force is F, then if the distance is decreased by 5 times, then the new gravitation force is:

F/5² = F/25

6 0

3 years ago

Describe why cars are inefficient machines in terms of thermodynamics.

Alina [70]

Cars are the mechanical device which convert chemical energy of fuel into mechanical energy, the engine used in the automobiles car are very inefficient, they can only convert 30-40% of chemical energy of fuel into mechanical energy, since thermodynamics is the branch of science that deals with the conversion of energy, thus due to poor conversion rate of chemical energy into mechanical energy, cars are known as inefficient machine.

6 0

3 years ago

Read 2 more answers

Suppose you wish to whirl a pail full of water in a vertical circle at a constant speed without spilling any of its contents (ev

Yanka [14]

Answer:

V = 2.87 m/s

Explanation:

The minimum speed required would be that at which the acceleration due to gravity is negated by the centrifugal force on the water.

Thus, we simply need to set the centripetal acceleration equal to gravity and solve for the speed V using the following equation:

Centripetal acceleration = V^2 / r

where r is the distance of water from the pivot or shoulder.

For our case, r will be 0.65 + 0.19 = 0.84 m

and solving the above equation we get:

9.81 = V^2 / 0.84

V^2 = 8.2404

V = 2.87 m/s

6 0

2 years ago