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gayaneshka [121]

3 years ago

7

A crate is sliding down a ramp that is inclined at an angle 30.6 ° above the horizontal. The coefficient of kinetic friction bet

ween the crate and the ramp is 0.360. Find the acceleration of the moving crate.

1 answer:

Vlada [557]3 years ago

6 0

Answer: $1.95 m/s^2$

Explanation:

Given

inclination $\theta =30.6^{\circ}$

coefficient of kinetic friction $\mu =0.36$

As crate is moving Down therefore friction will oppose the motion

using FBD

$mg\sin \theta -f_r=ma$

$f_r=\mu N$

$f_r=\mu mg\cos \theta$

$mg\sin \theta -\mu mg\cos \theta =ma$

$a=g\sin \theta -\mu g\cos \theta$

$a=g(\sin (30.6)-0.36\cdot \cos (30.6))$

$a=9.8\times 0.199$

$a=1.95 m/s^2$

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2 years ago

A 12.0kg microwave oven is pushed 14.0m up the sloping surface of a loading ramp inclined at an angle 37 degrees above the horiz

Semenov [28]

Answer:

Answered

Explanation:

a) What is the work done on the oven by the force F?

W = F * x

W = 120 N * (14.0 cos(37))

<<<< (x component)

W = 1341.71

b) $F_f=\mu_k N$

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c) increase in the internal energy

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= 991 J

d) the increase in oven's kinetic energy

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1341.71 J - 329 J - 991 J = K_2

K_2 = 21.71 J

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4 0

3 years ago

Suppose that we use a heater to boil liquid nitrogen (N2 molecules). 4480 J of heat turns 20 g of liquid nitrogen into gas. Note

love history [14]

Answer:

The energy is $9.4\times10^{-21}\ J$

(a) is correct option

Explanation:

Given that,

Energy = 4480 j

Weight of nitrogen = 20 g

Boil temperature = 77 K

Pressure = 1 atm

We need to calculate the internal energy

Using first law of thermodynamics

$Q=\Delta U+W$

$Q=\Delta U+nRT$

Put the value into the formula

$4480=\Delta U+\dfrac{20}{28}\times8.314\times77$

$\Delta U=4480-\dfrac{20}{28}\times8.314\times77$

$\Delta U=4022.73\ J$

We need to calculate the number of molecules in 20 g N₂

Using formula of number of molecules

$N=n\times \text{Avogadro number}$

Put the value into the formula

$N=\dfrac{20}{28}\times6.02\times10^{23}$

$N=4.3\times10^{23}$

We need to calculate the energy

Using formula of energy

$E=\dfrac{\Delta U}{N}$

Put the value into the formula

$E=\dfrac{4022.73}{4.3\times10^{23}}$

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Hence, The energy is $9.4\times10^{-21}\ J$

4 0

3 years ago

A student holds a bike wheel and starts it spinning with an initial angular speed of 9.0 rotations per second. The wheel is subj

KATRIN_1 [288]

Answer:

$\Delta t = 8 s$

Explanation:

As we know that the angular acceleration of the wheel due to friction is constant

so we can use kinematics

$\theta = \omega_i t + \frac{1}{2}\alpha t^2$

so we have

$(65 \times 2\pi) = (2\pi \times 9)(10) + \frac{1}{2}(\alpha)(10^2)$

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$\alpha = -\pi rad/s^2$

now time required to completely stop the wheel is given as

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$t = 18 s$

now time required to stop the wheel is given as

$\Delta t = 18 - 10$

$\Delta t = 8 s$

6 0

3 years ago