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2 years ago

A tourist stands at the top of the Grand Canyon, holding a rock, overlooking the valley

Physics

1 answer:

kkurt [141]2 years ago

8 0

Answer:

a. Vf = 39.24 [m/s]

b. Vf = 31.24 [m/s]

c. Vf = 47.24 [m/s]

Explanation:

To solve this problem we can use the following equation of kinematics. We have to keep in mind that the gravitational acceleration acts downwards, therefore when the rock falls towards the abyss it has the same direction of the acceleration and that is why the gravitational acceleration has a positive sign in the equation.

$v_{f}=v_{o}+g*t$

where:

Vf = final velocity [m/s]

Vo = initial velocity = 0 (when the rock is dropped)

g = gravitational acceleration = 9.81 [m/s²]

t = time = 4 [s]

$v_{f}=0+9.81*4\\v_{f}= 39.24 [m/s]$

In this particular situation, the acceleration will be taken as negative because the gravity is pointing in the opposite direction of the movement of the rock.

$v_{f}=8-(9.81*4)\\v_{f}=-31.24[m/s]$

The negative sign in the answer tells us that the rock no longer moves up instead it does downwards when 4 seconds have passed.

$v_{f}=8+(9.81*4)\\v_{f}=47.24[m/s]$

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A racecar experiences a centripetal acceleration of 36.0 m/s2 as it travels at a constant speed of 27.0 m/s along a circular arc

alexdok [17]

Answer:

20.25 m

Explanation:

Centripetal acceleration is given by; the square of the velocity, divided by the radius of the circular path.

That is;

ac = v²/r

Where; ac = acceleration, centripetal, m/s², v is the velocity, m/s and r is the radius, m

Therefore;

r = v²/ac

= 27²/36

= 20.25 m

Hence the radius is 20.25 meters

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3 years ago

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rjkz [21]

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Explanation: Hope this helped :)

8 0

2 years ago

A 50.0-kg block is being pulled up a 16.0Â° slope by a force of 250 n that is parallel to the slope. the coefficient of kinetic

Drupady [299]

When dealing with multiple forces acting on a body, it is advisable to draw a free-body diagram like that shown in the picture. There are four forces acting on the box: weight (W) pointing straight down, normal force perpendicular to the slope denoted as Fn, force used to push the box upwards along the slope and the frictional force acting opposite to the direction of motion of the box denoted as Ff. Frictional force is equal to coefficient of kinetic friction (μk) multiplied with Fn.

∑Fy = Fn - mgcos30° = 0
Fn = (50)(9.81)(cos 16) = 471.5 N

When in motion, the net force is equal to mass times acceleration according to Newton's 2nd Law of Motion:

Fnet = F - μk*Fn - mgsin30° = ma
250 - (0.2)(471.5 N) - (50)(sin 16°) = (50)(a)
a = 2.84 m/s²

8 0

3 years ago

Bernice draws an oxygen atom. She draws a small circle for the nucleus. Inside of the circle, she draws plus signs for protons a

Lelu [443]

Answer

It should be A and C

Explanation:

because oxygen is number 8 in the periodic table of elements and has a atomic weight of 15.999 you use those numbers to figure out what is true between those.

The 8 for oxygen goes for the number of electrons and proton and to find neutrons u round the 15.999 up which now make it 16 and subtract it by the 8 now you have 8 protons, 8 neutrons, and 8 electrons

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2 years ago

A car travelling at 5.0 m/s starts to speed up. After 3.0 s its velocity has increased to 11 m/s. a) What is its acceleration? (

lions [1.4K]

initially, the car is traveling at 5.0 m/s.

so, we know acceleration for changing velocity is :

a = (v-v $_{o}$ )/t ..........(i)

where v is the final velocity

v $_{o}$ is the initial velocity

t is the time taken to change velocity

Now, as per the question :

initial velocity, v $_{o}$ =5.0 m/s

final velocity, v =11 m/s

time taken, t = 3 s

putting the values in equation (i),

a = ( 11-5 )/3

a = 2 m/s²

Therefore, a, after 3 s, is 2 m/s².

4 0

1 year ago