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3 years ago

If a 42kg rolling object slows from 11.5 m/s to 3.33 m/s how much work does friction do?

Physics

1 answer:

lara31 [8.8K]3 years ago

4 0

Explanation:

work done by friction = 1/2 x 42 x ( 3.33^2 - 11.5^2)

= 21 ( 11.08 - 132.25)

= 21 ( - 121.17 )

= - 2544.57 J

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A roller coaster at the Six Flags Great America amusement park in Gurnee, Illinois, incorporates some clever design technology a

sergeinik [125]

Answer:

a)radius of the arc of the teardrop at the top is 10.58m

b)T = mg

c) the centipetal acceleration at the top is 14.5m/s

Explanation:

Part A

Given that roller coaster is of tear drop shape

So the speed at the top is given as

v = 14.4 m/s

acceleration at the top is given as

a = 2 g

$a = 2(9.8) = 19.6 m/s^2$

now we know the formula of centripetal acceleration as

$a = \frac{v^2}{R}\\$

$19.6 = \frac{14.4^2}{R}\\R = 10.58 m$

Part B

now

the total mass of the car and the ride is M

Let the force exerted by the track be n

By Newton law

$n +Mg =\frac{Mv^2}{r} \\\\n=\frac{Mv^2}{r} -Mg\\\\=M(\frac{v^2}{r}-g )\\\\=M(2g-g)\\\\T=Mg$

Part C

If the radius of the loop is 21.4 m

speed is given by same v = 14.4 m/s

now the acceleration is given as

$a = \frac{v^2}{R}$

$a = \frac{14.4^2}{21.4} \\\\= 9.69 m/s^2$

Now for normal force at the top is given by force equation

$F_n + mg = ma\\F_n = m(a-g)$

The force exerted by the rail is less than zero because acceleration is less than 9.69m/s²

So the normal force would have to point away from the centre, For safe ride this normal force must be positive i.e $a \prec g$

$\frac{v^2}{r} \prec \sqrt{g} \\\\v = \sqrt{rg} \\\\v = \sqrt{21.4 \times 9.8} \\\\v = 14.5m/s$

3 0

3 years ago

A 9.4 kg dog takes a nap in a canoe and wakes up to find the canoe has drifted out onto the lake but now is stationary. He walks

bekas [8.4K]

Answer:

28.2 kg

Explanation:

Data provided in the question:

Mass of dog, m = 9.4 kg

Velocity of the dog with respect to water, v = 0.48 m/s

Velocity of the canoe, V = - 0.16 m/s [ - sign means velocity in opposite direction]

Now,

Let the mass of canoe be 'M'

Therefore,

From the conservation of momentum, we have

⇒ mv + MV = 0

⇒ 9.4 × 0.48 + M(- 0.16) = 0

⇒ 4.512 - 0.16M = 0

⇒ 0.16M = 4.512

⇒ M = 28.2 kg

7 0

3 years ago

An explanation can be consistent but may not be the best explanation for a phenomenon

notka56 [123]

Answer:

true

Explanation:

8 0

3 years ago

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A toy gun uses a spring to project a 5.3 - g soft rubber sphere horizontally. The spring constant is 8.0 N/m, the barrel of the

Vikki [24]

Answer:

v = 1.16 m/s

Explanation:

As per work energy theorem we know that work done by all forces on the sphere is equal to the change in kinetic energy of the sphere

So here we will have

$\frac{1}{2}kx^2 - F_f .d = \frac{1}{2}mv^2$

here we know that

$F_f = 0.032 N$

k = 8 N/m

now we have

$\frac{1}{2}(8)(0.05^2) - (0.032)(0.15 + 0.05) = \frac{1}{2}(0.0053)v^2$

$0.01 - 6.4 \times 10^{-3} = 2.65 \times 10^{-3} v^2$

$v = 1.16 m/s$

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4 years ago

How many times farther is Proxima Centauri from the sun than is earth from the sun

Aleks04 [339]

Answer:

Of the three stars in the system, the dimmest - called Proxima Centauri - is actually the nearest star to the Sun. The two bright stars, called Alpha Centauri A and B form a close binary system; they are separated by only 23 times the Earth - Sun distance.

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3 years ago

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