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love history [14]

2 years ago

15

Which of the following is an example of increasing friction intentionally? a. waxing skis b. adding grease to gears on a bike c.

throwing sand on an icy driveway d. oiling a squeaky door Please select the best answer from the choices provided

1 answer:

Aleonysh [2.5K]2 years ago

7 0

C i think that it tell me if its wrong

You might be interested in

The gravitational force between two objects is 100 N.

defon

200N is the answer (at least thats what I think)

5 0

2 years ago

Thermal conductivity of a material is given as 129Btuft–¹ h–¹°F–¹.Calculate this thermal conductivity in Jm–¹s–¹°C–¹(Given: 1Btu

ss7ja [257]

Answer:

223.25 $\text{Jm}^{-1}\text{s}^{-1}^\circ\text{C}^{-1}$

Explanation:

The thermal conductivity of an object is defined as the measure or the ability of the object to transfer heat or conduct heat through its body.

In the context, the thermal conductivity of the material is given as

$=129 \text{ Btu ft}^{-1}\text{h}^{-1}^\circ\text{F}^{-1}$

And it is given that :

1 Btu = 1055 J

1 ft = 0.3048 m

$1^\circ F = \frac{5}{9}^\circ C$

We know that 1 h = 3600 s

So the thermal conductivity of the material in $\text{Jm}^{-1}\text{s}^{-1}^\circ\text{C}^{-1}$ is :

Thermal conductivity :

$=\frac{129 \text{ Btu}}{1 \text{ ft }\times \text{1 h}\times 1^\circ\text{F}}$

$=\frac{129 \times 1055 \text{ J}}{0.3048 \text{ m} \ \times 3600 \text{ s}\ \times \frac{5}{9}^\circ \text{C}}$

= 223.25 $\text{Jm}^{-1}\text{s}^{-1}^\circ\text{C}^{-1}$

3 0

2 years ago

An 20-cm-long bicycle crank arm, with a pedal at one end, is attached to a 25-cm-diameter sprocket, the toothed disk around whic

Andrej [43]

Answer:

0.033815 m/s²

12.48810875 m

Explanation:

t = Time taken = 12 s

$\omega_f$ = Final angular velocity = 95 rpm

$\omega_i$ = Initial angular velocity = 64 rpm

$\alpha$ = Angular acceleration

$\theta$ = Angle of rotation

$\omega_f=\omega_i+\alpha t\\\Rightarrow \alpha=\frac{\omega_f-\omega_i}{t}\\\Rightarrow \alpha=\frac{95\times \frac{2\pi}{60}-64\times \frac{2\pi}{60}}{12}\\\Rightarrow \alpha=0.27052\ rad/s^2$

Tangential acceleration is given by

$a_t=\alpha r\\\Rightarrow a_t=0.27052\times 0.125\\\Rightarrow a_t=0.033815\ m/s^2$

The tangential acceleration of the pedal is 0.033815 m/s²

$\omega_f^2-\omega_i^2=2\alpha \theta\\\Rightarrow \theta=\frac{\omega_f^2-\omega_i^2^2}{2\alpha}\\\Rightarrow \theta=\frac{\left(95\times\frac{2\pi }{60}\right)^2-\left(64\times\frac{2\pi}{60}\right)^2}{2\times 0.27052}\\\Rightarrow \theta=99.90487\ rad$

Linear displacement would be $99.90487\times \frac{1}{2\pi}\times 2\pi\times 0.125=12.48810875\ m$

Length of chain that passes in the interval is 12.48810875 m

4 0

3 years ago

A magnet in the form of a cylindrical rod has a length of 5.51 cm and a diameter of 0.865 cm. It has a uniform magnetization of

andriy [413]

Answer:

Magnetic dipole moment will be $15.51\times 10^{-3}J/T$

Explanation:

We have given length of the cylinder , that is h = 5.51 cm = 0.051 m

And diameter of the cylinder d = 0.865 cm

So radius $r=\frac{d}{2}=\frac{0.865}{2}=0.4325cm=0.4325\times 10^{-2}m$

So volume of cylinder $V=\pi r^2h=3.14\times (0.4325\times 10^{-2})^2\times 0.051=3\times 10^{-6}m^3$

It is given there is uniform magnetization of $M=5.17\times 10^3A/m$

We have to fond the dipole moment

Dipole moment is equal to $\mu =MV$ , here M is magnetization and V is volume

So $\mu =MV=5.17\times 10^3\times 3\times 10^{-6}=15.51\times 10^{-3}J/T$

5 0

3 years ago

Which of the following does not contribute to Wellness

Tomtit [17]

<span>The option that does not contribute to wellness are tendencies. Tendencies are just things that you are more likely to do, or behavior that you are more likely to show, and in no way does that affect your wellness. However, your habits, exercise, and diet do, because all of these things have an impact on both your body and mind, thus creating a wellness of the entire human being.</span>

4 0

2 years ago