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olga nikolaevna [1]
3 years ago
5

You're riding a unicorn at 25 m/s and come to a uniform stop at a red light 20m away. What's your acceleration?

Physics
2 answers:
NNADVOKAT [17]3 years ago
8 0

The answer is -15.625m/s².


Acceleration is the change in velocity over a period of time. It can be computed using the formula:


a = \dfrac{vf-vi}{t}

Where:

vf = final velocity

vi = initial velocity

t = time

Now let's see what was given in your problem:

The car was moving at 25m/s and then came to a stop. So initially it was moving and then it stopped. This means the final velocity will be 0m/s because it stopped moving.


But look at the problem, it shows no time. We need to solve for time from the time it moved till it reached the red light 20 m away.


Time can be computed using the kinematics formula:

d = \dfrac{vi+vf}{2} *t


We just derive the formula from the equation by filling out what we know first. 

20m = \dfrac{25m/s+0m/s}{2}(t)

20m = 12.5m/s{2}(t)

\dfrac{20m}{12.5m/s}=t
1.6s=t

The time it took from the point it was moving till it stopped is 1.6s. We can now use this in our acceleration formula.


a = \dfrac{0m/s-25m/s}{1.6s}

a = \dfrac{-25m/s}{1.6s}

a = -15.625m/s^{2}


Notice that the acceleration is negative. This means that the car decelerated or slowed down.

strojnjashka [21]3 years ago
5 0

Answer:

My acceleration is 15.63 m/s² (slowing down)

Explanation:

The expression for the acceleration is equal:

v^{2} _{f} -v^{2} _{i} =2ax

Where

vi = initial speed = 25 m/s

vf = final speed = 0

x = displacement = 20 m

Replacing and clearing the acceleration "a":

a=\frac{v^{2} _{f} -v^{2} _{i} }{2x} =\frac{0-25^{2} }{2*20} =--15.63m/s^{2}

The negative sign of acceleration means that it is slowing down

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Alan starts from his home and walks 1.3 km east to the library. He walks an additional 0.68 km east to a music store. From there
zepelin [54]

Answer: final Displacement = 0 km, total distance covered =7 km

Explanation:

Given the following :

From home to library = 1.3 km East

Library to music store = 0.68km East

Music store to friend's house = 1.1km North

Friend's house to grocery store = 0.42 km North

Displacement is the net change in distance traveled.

Eastward distance :

To = (1.3 + 0.68)km = 1.98km East

Fro = (0.68 + 1.3)km = 1.98 km East

Δ distance = (1.98 - 1.98) = 0

Northward direction:

To = (1.1 + 0.42)km = 1.52km north

Fro = (0.42 + 1.1)km = 1.52km North

Δ distance = (1.98 - 1.98) = 0

Hence final Displacement = 0

Total distance covered = 2 × (1.3 + 0.68 + 1.1 + 0.42) = 2 × 3.5

= 7km

3 0
3 years ago
A 15-lb block B starts from rest and slides on the 25-lb wedge A, which is supported by a horizontal surface. Neglecting frictio
xxTIMURxx [149]

The angle of the wedge is 30°.

Answer:

5.88 ft/s

Explanation:

a) The block will slide down due to it's weight.

initial velocity u= 0

final velocity, v

acceleration, a = g sin 30° = 32 ft/s²× sin 30° = 16 ft/s²

Sliding displacement, s = 3ft

Use third equation of motion:

v^2-u^2 = 2as

substitute the values and solve for v

v^2-0 = 2\times 16 \times 3 =96 ft^2/s^2\\v = 9.8 ft/s

b) Use conservation of momentum:

Initial momentum of the system  = 0

final momentum = (15) ( 9.8)+ (25)(v')

v' = 5.88 ft/s

3 0
3 years ago
If a car moves with a uniform speed of 2m/s in a circle of radius 0.4m, what is its angular speed?
REY [17]

Answer:

The car's angular speed is \frac{rad}{s}.

Explanation:

Angular velocity is usually measured with \frac{radians}{sec}, so I'm going to use that to answer your question.

The relationship between tangential velocity and angular velocity (ω)  is given by:

V = \omega R

Using the values from the question, we get:

2 \frac{m}{s} = \omega (0.4m)

\omega = 5 \frac{rad}{s}

Therefore, the car's angular speed is 5 \frac{rad}{s}.

Hope this helped!

3 0
3 years ago
un futbolista patea una pelota que se encuentra en el pasto con un angulo de 30° (medido desde la horizontal) con la intención d
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Answer:

i dont really know what it is

8 0
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8_murik_8 [283]

Explanation:

1)

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B) 50%

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