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3 years ago

How do you find a rate of deceleration

Physics

2 answers:

maxonik [38]3 years ago

7 0

To find the deceleration of the object. We need to know what is the speed the object is slowing down to, in this case it would be final velocity of 0.

Vi = 75
Vf = vi + at
0 = 300a + 75
-75 m/s = 300a
-75/300 = a
-0.25 m/s^2 = a.

The train slows down at this rate a = -0.25 m/s^2.

5 min = 5 • 60 = 300 seconds

Irina18 [472]3 years ago

4 0

To find the rate of deceleration, subtract the initial velocity from the final velocity.

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According to the exercise principle of balance, a workout should __________.

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a. address all components of fitness

According to the exercise principle of balance, a workout should address all components of fitness.
NOT:
b. focus on balance and coordination
c. target specific areas for improvement 
d. vary exercise activities over time

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3 years ago

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Draw a Lewis dot structure for Hf

Serjik [45]

Answer:

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Explanation:

mark me brainliest!!

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2 years ago

A record turntable is rotating at 33 rev/min. A watermelon seed is on the turntable 4.0 cm from the axis of rotation. (a) Calcul

Annette [7]

Answer:

a) a = 0.477 m/s^2

b) u = 0.04862

Explanation:

Given:-

- The rotational speed of the turntable N = 33 rev/min

- The watermelon seed is r = 4.0 cm away from axis of rotation.

Find:-

(a) Calculate the acceleration of the seed, assuming that it does not slip. (b) What is the minimum value of the coefficient of static friction between the seed and the turntable if the seed is not to slip

Solution:-

- First determine the angular speed (w) of the turntable.

w = 2π*N / 60

w = 2π*33 / 60

w = 3.456 rad/s

- The watermelon seed undergoes a centripetal acceleration ( α ) defined by:

α = w^2 * r

α = 3.456^2 * 0.04

α = 0.477 m / s^2

- The minimum friction force (Ff) is proportional to the contact force of the seed.

- The weight (W) of the seed with mass m acts downwards. The contact force (N) can be determined from static condition of seed in vertical direction.

N - W = 0

N = W = m*g

- The friction force of the (Ff) is directed towards the center of axis of rotation, while the centripetal force acts in opposite direction. The frictional force Ff = u*N = u*m*g must be enough to match the centripetal force exerted by the turntable on the seed.

Ff = m*a

u*m*g = m*a

u = a / g

u = 0.477 / 9.81

u = 0.04862

8 0

2 years ago

A body is dropped from the roof of a 20 m high building by how much:

USPshnik [31]

Answer:

t = 2.01 s

Vf = 19.7 m/s

Explanation:

It's know through the International System that the earth's gravity is 9.8 m/s², then we have;

Data:

Height (h) = 20 m
Gravity (g) = 9.8 m/s²
Time (t) = ?
Final Velocity (Vf) = ?

==================================================================

Time

Use formula:

$\boxed{t=\sqrt{\frac{2*h}{g}}}$

Replace:

$\boxed{t=\sqrt{\frac{2*20m}{9.8\frac{m}{s^{2}}}}}$

Everything inside the root is solved first. So, we solve the multiplication of the numerator:

$\boxed{t=\sqrt{\frac{40m}{9.8\frac{m}{s^{2}}}}}$

It divides:

$\boxed{t=\sqrt{4.08s}}$

The square root is performed:

$\boxed{t=2.01s}$

==================================================================

Final Velocity

use formula:

Vf = g * t

Replace:

Vf = 9.8 m/s² * 2.01 s

Multiply:

Vf = 19.7 m/s

==================================================================

How long does it take to reach the ground?

Takes time to reach the ground in 2.01 seconds.

How fast does it hit the ground?

Hits the ground with a speed of 19.7 meters per seconds.

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3 years ago

A sprinter set a high school record in track and field, running 200.0 m in 20.6 s . what is the average speed of the sprinter in

Paraphin [41]

Answer : The average speed of the sprinter is, 34.95 Km/hr

Solution :

Average velocity : It is defined as the distance traveled by the time taken.

Formula used for average velocity :

$v_{av}=\frac{d}{t}$

where,

$v_{av}$ = average velocity

d = distance traveled = 200 m

t = time taken = 20.6 s

Now put all the given values in the above formula, we get the average velocity of the sprinter.

$v_{av}=\frac{200m}{20.6s}\times \frac{3600}{1000}=34.95Km/hr$

conversion :

(1 Km = 1000m)

(1 hr = 3600 s)

Therefore, the average speed of the sprinter is, 34.95 Km/hr

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2 years ago

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