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2 years ago

13

What is the acceleration of a train that takes 22 seconds to go from a speed of 73 kilometers per hour to a speed of 45 kilomete

rs per hour?

1 answer:

gladu [14]2 years ago

4 0

Answer:

.354 m/s^2

Explanation:

Acceleration is change in velocity divided by change in time

(73 - 45 ) = 28 km / hr velocity change this is 7.778 m/s

7.778 m/s / 22 s = .354 m/s^2

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Consider three scenarios in which a particular box moves downward under the pull of gravity :

luda_lava [24]

Answer:

1. True WA > WB > WC

Explanation:

In this exercise they give work for several different configurations and ask that we show the relationship between them, the best way to do this is to calculate each work separately.

A) Work is the product of force by distance and the cosine of the angle between them

WA = W h cos 0

WA = mg h

B) On a ramp without rubbing

Sin30 = h / L

L = h / sin 30

WB = F d cos θ

WB = F L cos 30

WB = mf (h / sin30) cos 30

WB = mg h ctan 30

C) Ramp with rubbing

W sin 30 - fr = ma

N- Wcos30 = 0

W sin 30 - μ W cos 30 = ma

F = W (sin30 - μ cos30)

WC = mg (sin30 - μ cos30) h / sin30

Wc = mg (1 - μ ctan30) h

When we review the affirmation it is the work where there is rubbing is the smallest and the work where it comes in free fall at the maximum

Let's review the claims

1. True The work of gravity is the greatest and the work where there is friction is the least

2 False. The job where there is friction is the least

3 False work with rubbing is the least

4 False work with rubbing is the least

5 0

3 years ago

Describe how the student should measure the time taken for the toy parachute to

PolarNik [594]

The time must be measured with respect to gravity. As it falls, it has free fall that is the force acting on it will be the gravity.With the distance in account, d = 1/2 gt²

t = √(2d/g)

4 0

2 years ago

WILL GIVE BRAINLIEST AND 30 POINTS!

mariarad [96]

Answer:

Gallium

Explanation:

Gallium is one such element used as a do/pant in a p-type semiconductor.

A do/pant is an impurity added to a semi-conductor used to alter its properties. Semi-conductors have a wide range of applications. They will conduct heat and electricity only under certain conditions. This property is highly desirable and find a wide application in electronics.

For p-type conductors, they are best do/ped with elements with 3 valence electrons. These are group 3 elements. From the choices, only gallium belongs to this group.

Other elements given are good do/pants for n-type semiconductors. They have 5 valence electrons.

8 0

3 years ago

A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 3.9 m/s. The car is a distanc

sammy [17]

If it takes $t$ seconds to reach the car, then the distance $d$ is $3.9t$ .

The bear's distance from the tourist's starting point is
$6t-23$

For maximum $d$ , we set the equations equal to each other:
$3.9t=6t-23$
$\Rightarrow -2.1t=-23$
$\Rightarrow t=\frac{23}{2.1}$
so the distance is
$d=3.9(\frac{23}{2.1})\approx42.741\ m$

6 0

2 years ago

A student, standing on a scale in an elevator at rest, sees that his weight is 840 N. As the elevator rises, his weight increase

ololo11 [35]

As per FBD while its accelerating upwards

we can say that

$F_n - mg = ma$

here normal force is given as

$F_n = 1050 N$

$W = 840 N$

now mass is given as

$m(9.8) = 840$

$m = 85.7 kg$

now we will have

$1050 - 840 = 85.7 \times a$

$a = 2.45 m/s^2$

Now while accelerating downwards we can say by FBD

$mg - F_n = ma$

again plug in all values

$840 - 588 = 85.7 \times a$

$a = 2.94 m/s^2$

5 0

3 years ago