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ludmilkaskok [199]
3 years ago
8

The driver of a car travels at 90 km / h, observes some children playing on the road 50 m away, and applies the brakes, managing

to stop 4 seconds later, if the total mass of the driver-vehicle system is 2200 kg What was the force developed by the brakes? Was there an accident? Explain with mathematical arguments, please help.
Physics
1 answer:
Orlov [11]3 years ago
6 0

Answer:

13,750 N

Yes

Explanation:

Given:

v₀ = 90 km/h = 25 m/s

v = 0 m/s

t = 4 s

Find: a and Δx

a = Δv / Δt

a = (0 m/s − 25 m/s) / (4 s)

a = -6.25 m/s²

F = ma

F = (2200 kg) (-6.25 m/s²)

F = -13,750 N

Δx = ½ (v + v₀) t

Δx = ½ (0 m/s + 25 m/s) (4 s)

Δx = 50 m

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The New Horizons probe that passed by Pluto during July 2015 is one of the fastest spacecraft ever assembled. It was moving at a
LenKa [72]

Answer:

2.91 x 10¹² sec

Explanation:

d = distance of nearest star, Proxima Centauri  = 4.3 ly = 4.3 x 9.46 x 10¹⁵ m

v = speed of new horizon probe = 14 km/hr = 14000 m/s

t = time taken for the new horizon probe to reach nearest star, Proxima Centauri = ?

Using the equation

d = v t

Inserting the values given

4.3 x 9.46 x 10¹⁵ = (14000) t

t = 2.91 x 10¹² sec

7 0
3 years ago
What are the two sources of earth's internal heat energy
RUDIKE [14]

Answer:

Hey

Your answer would be Radioactive Decay and Heat of formation.

When earth first formed it was very violant. Some planetary scientists believe that the moon was created from a collision involving earth and Thea (a theoretical dwarf planet). these collisions that have formed earth heated it so much that it is still hot from them.

Radioactivce decay is another major fource of internal heat for earth.

6 0
2 years ago
Approximately how many atoms are there along a 9.5 cm line
uranmaximum [27]
First convert 5.5 cm to meters.

(5.5 cm / 1) x (m / 100 cm) = 0.055 m

A typical atom is about 1.0E-10 m in diameter; thus:

0.055 m / 1.0E-10 m = 5.5E8 atoms or 550,000,000 end-to-end atoms in 5.5 cm
4 0
3 years ago
Gravity is defined as: Select one: a. an apple falling from a tree toward the ground. b. ability to accomplish a job with the le
Scorpion4ik [409]

Answer:

c. natural force or pull toward the earth

Explanation:

Gravity of the earth is the force of attraction that it naturally possesses to attract any mass.

An apple falls on the earth due to this force of gravity.

The force of gravity near to the surface of the earth is given as:

F=m.g

where:

m= mass of the body

g= acceleration due to gravity

The variation of the gravitational force with height is given as:

F'=m.g'

where:

g'=g\times (1+\frac{h}{R} )^{-2}

where

R = radius of the earth \approx64000\ km

4 0
3 years ago
g An electron enters a region of space containing a uniform 1.63 × 10 − 5 T magnetic field. Its speed is 121 m/s and it enters p
kolbaska11 [484]

Answer:

i. The radius 'r' of the electron's path is 4.23 × 10^{-5} m.

ii. The frequency 'f' of the motion is 455.44 KHz.

Explanation:

The radius 'r' of the electron's path is called a gyroradius. Gyroradius is the radius of the circular motion of a charged particle in the presence of a uniform magnetic field.

                 r = \frac{mv}{qB}

Where: B is the strength magnetic field, q is the charge, v is its velocity and m is the mass of the particle.

From the question, B = 1.63 × 10^{-5}T, v = 121 m/s, Θ = 90^{0} (since it enters perpendicularly to the field), q = e  = 1.6 × 10^{-19}C and m = 9.11 × 10^{-31}Kg.

Thus,

         r = \frac{mv}{qB} ÷ sinΘ

But,  sinΘ =  sin 90^{0} = 1.

So that;

          r = \frac{mv}{qB}

            = (9.11 × 10^{-31} × 121) ÷ (1.6 × 10^{-19}  × 1.63 × 10^{-5})

            = 1.10231 × 10^{-28}   ÷ 2.608 × 10^{-24}

            = 4.2266 × 10^{-5}

            = 4.23 × 10^{-5} m

The radius 'r' of the electron's path is 4.23 × 10^{-5} m.

B. The frequency 'f' of the motion is called cyclotron frequency;

           f = \frac{qB}{2\pi m}

             =  (1.6 × 10^{-19}  × 1.63 × 10^{-5}) ÷ (2 ×\frac{22}{7} × 9.11 × 10^{-31})

             =  2.608 × 10^{-24} ÷  5.7263 × 10^{-30}

             = 455442.4323

          f  = 455.44 KHz

The frequency 'f' of the motion is 455.44 KHz.

3 0
3 years ago
Read 2 more answers
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