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3 years ago

Questions from chapter 8.rotational of a rigid body

Physics

1 answer:

LUCKY_DIMON [66]3 years ago

7 0

the moment of inertia of wheel= 1/2mr²

m= mass of wheel= 2.8 kg

r= radius

i= 1/2 (2.8)(0.35)²=0.1715 kgm²

(a) torque = F r

F= force=5 N

r= radius=0.35 m

τ= 5 (0.35)

τ= 1.75 Nm

(b) for angular acceleration, we use

τ= iα

τ= torque= 1.75 Nm

i= moment of inertia=0.1715 kgm²

so 1.75 =0.1715 α

α=10.2 rad/s²

θ= ωo t + 1/2α t²

ωo= initial angular velocity=0

t= time=4 s

α= angular acceleration=10.2 rad/s²

so θ = 0 (4) + 1/2 (10.2)(4)²

θ=81.6 rad

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KiRa [710]

Answer: 4 ft/s

Explanation:

Given

height of man $=4 ft$

speed of person $v=8 ft/s$

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3 years ago

A maintenance worker wants to torque an engine bolt to 65.0 N m. If the torque wrench is 35cm in length, what is force applied t

harina [27]

Answer:

Force = 186 N

Explanation:

Torque is the rotational equivalent of linear force. It can be easely calculated using the formula :

$Torque = \vec{r} \times \vec{F}$

Where $\vec{r}$ is a vector that from the origin of the coordinate system to the point at which the force is applied (the position vector), $\vec{F}$ is the applied force.

The easiest way of computing the force is by setting the origin of the coordinate system to the lowest point of the torque wrench. By doing this we have that $r$ (the magnitud of the position vector) is 35cm.

Before computing the force we need to set all our values to the international system of units (SI). The torque is already in SI. The one missing is the length of the torque wrench (it is in centimeters and we need it in meters). So :

$35cm * \dfrac{1m}{100cm} = 0.35m$

Now using the torque formula:

$Torque = \vec{r} \times \vec{F}$

$Torque = rFsin(\theta)}$

Where $\theta$ is the smaller angle between the force and the position vector. Because the force is applied perpendiculary to the position vector $\theta = 90°$ , thus :

$Torque = rFsin(\theta)}$

$65 N m = (0.35m)Fsin(90°)}$

$F = \dfrac{65N m} {(0.35m)sin(90°)}$

$F = \dfrac{1300} {7}N$

so the force is approximately 186 N.

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4 years ago

a car with a mass of 2,000 kilograms is moving around a circular curve at a uniform velocity of 25 meters per second. the curve

Ber [7]

Fc=mv^2/r so we get

2000kg*(25m/s)^2/(80m)= 15625N of force

hope this helps! Thank You!!

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3 years ago

The medium through which a mechanical wave passes can be a solid, liquid, or gas. Properties of a wave change when it moves from

Tpy6a [65]

Answer:

Option A

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Mechanical waves requires some medium to travel through. They travel faster in the dense medium as compared to a free medium.

The speed of a mechanical wave is fastest in the solid medium and the slowest in the gaseous medium. Hence, as the wave traverses from gaseous medium to the solid medium, its speed increases.

Thus, option A is correct

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3 years ago

svetoff [14.1K]

D.) In order to calculate both of them, we must know the "FORCE" on the system.

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3 years ago

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