The rotating arm starts from rest and acquires a rotational speed N = 600 rev/min in 2 seconds with constant angular acceleration. Find the time t after starting before the acceleration vector of end P makes an angle of 45 with the arm OP

Respuesta :

Answer:

The time after starting is 0.178 sec.

Explanation:

Given that,

Rotational speed = 600 rev/min

Time t = 2 sec

Angle = 45

Distance OP= 6''

According to figure,

We need to calculate the angular acceleration

Using formula of angular acceleration

[tex]\alpha=\dfrac{\omega}{t}[/tex]

[tex]\alpha=\dfrac{\dfrac{2\piN}{60}}{t}[/tex]

Put the value into the formula

[tex]\alpha=\dfrac{\dfrac{2\times\pi\times600}{60}}{2}[/tex]

[tex]\alpha=10\pi\ rad/s62[/tex]

We need to calculate the tangential acceleration

Using formula of tangential acceleration

[tex]a_{t}=OP\times \alpha[/tex]

Put the value into the formula

[tex]a_{t}=6\times10\pi[/tex]

[tex]a_{t}=60\pi\ in/s^2[/tex]

We need to calculate the normal acceleration

Using formula of normal acceleration

[tex]a_{n}=OP\times\omega^2[/tex]

For angle [tex]\theta=45[/tex]

[tex]a_{n}=a_{t}[/tex]

Put the value into the formula

[tex]OP\times\omega^2=60\pi[/tex]

[tex]6\times\omega^2=60\pi[/tex]

[tex]\omega^2=10\pi[/tex]

[tex]\omega=\sqrt{10\pi}[/tex]

[tex]\omega=5.605\ rad/s[/tex]

We need to calculate the time

Using the kinematics equation

[tex]\omega=\omega_{0}+\alpha t[/tex]

Put the value into the formula

[tex]5.605=0+10\pi t[/tex]

[tex]t=\dfrac{5.605}{10\pi}[/tex]

[tex]t=0.178\ sec[/tex]

Hence, The time after starting is 0.178 sec.

Ver imagen CarliReifsteck