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3 years ago

1. Explain how a boulder at rest on the ground can actually be moving at the same time.

Physics

1 answer:

Mars2501 [29]3 years ago

8 0

Answer:

I don't know about the 1st one but An object at rest stays at rest and an object in motion stays in motion at a constant speed and direction unless acted upon by an unbalanced force. Or maybe its moving because the earth is moving and gravity is pulling it with.

2. Speed is the rate at which something or someone is able to move. Instantaneous Speed - the speed at any given instant in time. Average Speed - the average of all instantaneous speeds; found simply by a distance/time ratio.

3. Speed = distance divided by time or $s=\frac{d}{t}$ . Some units for speed can be miles, kilometres, feet, or metres.

4. Speed is the time rate at which an object is moving along a path, while velocity is the rate and direction of an object's movement. Put another way, speed is a scalar value, while velocity is a vector.

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A water balloon is dropped out of a fifth floor window and hits an unsuspecting person below 4.0 seconds later. The window is ap

andrew11 [14]

Answer:

80 meters high

Explanation:

The velocity of the balloon would be g*t (I won't calculate, but will us this later)

We know that the kinetic energy at the bottom equals the potential at the top.

KE = PE

1/2 * m * v^2 = m * g * h

1/2 * m * (g * t)^2 = m * g * h (substitution)

1/2 * m * g^2 * t^2 = m * g * h

1/2 * g * t^2 = h (simplification by dividing the commons between both sides)

h = 1/2 * 9.81 * 4^2

h = 78.48 m (roughly 80 m)

4 0

4 years ago

Please help!

FinnZ [79.3K]

(A) The speed of the pendulum when it reaches the bottom is 3.83 m/s.

(B) The speed of the pendulum when it reaches the bottom after losing 18% of its energy is 3.47 m/s.

(D) When the pendulum stops swinging, it has used all its energy to overcome frictional force of air.

<h3>Speed of the pendulum when it reaches the bottom</h3>

Apply the principle of conservation of energy;

K.E = P.E

¹/₂mv² = mgh

v² = 2gh

v = √2gh

v = √(2 x 9.8 x 0.75)

v = 3.83 m/s

<h3>Speed pendulum after losing 18% of the its initial energy</h3>

K.E = (100 - 18)P.E

¹/₂mv² = 0.82mgh

V = √(0.82 x 2gh)

v = √(0.82 x 2 x 9.8 x 0.75)

v = 3.47 m/s

<h3>Height reached when its looses another 7%</h3>

K.E = 0.5(1)(3.47)² = 6.02 J

When it losses 7% = 6.02 - (0.07 x 6.02) = 5.598 J

Height reached:

mgh = 5.598

h = 5.598/mg

h = 5.598/(1 x 9.8)

h = 0.57 m

<h3>Final energy of the pendulum</h3>

When the pendulum stops swinging, it has used all its energy to overcome frictional force of air.

Thus, the speed of the pendulum when it reaches the bottom is 3.83 m/s.

The speed of the pendulum when it reaches the bottom after losing 18% of its energy is 3.47 m/s.

The height reached by the pendulum after losing another 7% of its energy is 0.57 m.

Learn more about speed of pendulum here: brainly.com/question/13655641

#SPJ1

5 0

2 years ago

Formular for calculating resistors in parallel

JulijaS [17]

Answer:

1/Rt = 1/R1 + 1/R2 + 1/R3 +...

Explanation:

3 0

3 years ago

If the density of an object is 30 g/cm3 and its volume is 10 cm3, what is its mass in grams?

Inga [223]

Density = Mass / Volume

Mass = Density * Volume

Mass = 30 g/cm³ * 10 cm³ = 300 g

Mass = 300 g

7 0

3 years ago

Question:

klio [65]

The mass of the car should be A) 1212 kg

Explanation:

We can solve the problem by using Newton's second law of motion, which states that

$F=ma$

where:

F is the force produced by the engine

m is the mass of the car

a is its acceleration

In the first situation we have

m = 1515 kg

$a=12 m/s^2$ is the acceleration

Solving for F, we find the force produced by the engine:

$F=(1515)(12)=18,180 N$

Now we want the car to reach an acceleration of

$a'=15 m/s^2$

Using the same engine, therefore the force produced is still

F = 18,180 N

Re-arranging the equation for m', we find what should be the new mass of the car:

$F=m'a'\\m' = \frac{F}{a'}=\frac{18180}{15}=1212 kg$

Learn more about Newton's second law:

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6 0

4 years ago

Read 2 more answers