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3 years ago

Help me please!! 15points

Physics

1 answer:

Romashka-Z-Leto [24]3 years ago

4 0

Explanation:

Acceleration is the change in speed over change in time.

a = Δv / Δt

a. The car's acceleration is:

a = (80 km/h − 0 km/h) / 10 s

a = 8 km/h/s

So every second, the speed increases by 8 km/h.

b. The cyclist's acceleration is:

a = (16 m/s − 4.0 m/s) / 5.6 s

a = 2.1 m/s²

c. The stone's speed is:

10.0 m/s² = (v − 0 m/s) / 3.5 s

v = 35 m/s

d. The time is:

1.6 m/s² = (10 m/s − 0 m/s) / t

t = 6.3 s

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I need this type out answer question.

AveGali [126]

Answer:

The ball has 7.35 joules of energy at position B.

The velocity of the ball at position A is 3.13 meter/second

Explanation:

Kinetic and Gravitational Potential Energy

Kinetic energy is the form of energy that an object or a particle has by reason of its motion. An object of mass m and speed v has kinetic energy calculated by:

$\displaystyle K=\frac{1}{2}m.v^2$

Gravitational Potential Energy is the form of energy that an object has by reason of its height h relative to a certain reference. It can be calculated as follows:

$U=m.g.h$

Where g is the acceleration of gravity.

The figure shows a pendulum with a bob (ball) of mass m=1.5 Kg. When it's pulled to point B, it has a height of h= 0.5 m and set to rest.

The potential energy at that point is:

$U=1.5\ Kg\cdot 9.8 \ m/s^2\cdot 0.5\ m$

$U=7.35\ J$

The ball has 7.35 joules of energy at position B.

When the ball is released, all of the potential energy is transformed into kinetic energy when reaches point A. Thus:

K=7.35 J

From the equation of kinetic energy, we solve for v:

$\displaystyle v=\sqrt{\frac{2K}{m}}$

$\displaystyle v=\sqrt{\frac{2\cdot 7.35}{1.5}}$

$\displaystyle v=\sqrt{\frac{14.7}{1.5}}$

$\displaystyle v=\sqrt{9.8}$

v = 3.13 m/s

The velocity of the ball at position A is 3.13 meter/second

8 0

3 years ago

During an experiment, your teacher gives you two objects: tissue paper and a balloon. You observe that the tissue paper repels t

Galina-37 [17]

Answer:

i think your answer is this: the objects have no interactive with each other.

Explanation:

if you think about it tissue paper doesn't really have a static electrical charge if it does it is very weak so therefore cannot really attract or repel anything.

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2 years ago

Read 2 more answers

How do massive stars change the atmosphere?

Wewaii [24]

Not sure what you're referring to... our atmosphere is mostly nitrogen/oxygen - both gases were created by very massive stars, many times greater than our sun - our sun isn't massive enough to create the gases needed for our atmosphere...

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3 years ago

A Christmas light is made to flash via the discharge of a capacitor. The effective duration of the flash is 0.25 s (which you ca

Sonbull [250]

Answer:

The correct solution is:

(a) $1.375\times 10^{-2} \ J$

(b) $4.43\times 10^{-3} \ C$

(c) $1.42\times 10^{-3} \ F$

(d) $178.57 \ \Omega$

Explanation:

The given values are:

Effective duration of the flash,

ζ = 0.25 s

Average power,

$P_{avg}=55 \ mW$

$=55\times 10^{-3} \ W$

Average voltage,

$V_{avg}=3.1 \ V$

Now,

(a)

⇒ $E=P_{avg}\times \zeta$

On substituting the values, we get

⇒ $=55\times 10^{-3}\times 0.25$

⇒ $=1.375\times 10^{-2} \ J$

(b)

⇒ $E=Q\times V_{avg}$

then,

⇒ $Q=\frac{E}{V_{avg}}$

On substituting the values, we get

⇒ $=\frac{1.375\times 10^{-2}}{3.1}$

⇒ $=4.43\times 10^{-3} \ C$

(c)

⇒ $C=\frac{Q}{V}$

⇒ $=\frac{4.43\times 10^{-3}}{3.1}$

⇒ $=1.42\times 10^{-3} \ F$

(d)

As we know,

⇒ $R=\frac{1}{4C}$

⇒ $=\frac{1}{4\times 1.42\times 10^{-3}}$

⇒ $=\frac{1000}{5.6}$

⇒ $=178.57 \ \Omega$

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2 years ago

A 12.0-kg shell is launched at an angle of 55.0 ∘ above the horizontal with an initial speed of 150 m/s. when it is at its highe

Stolb23 [73]

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3 years ago