Ask question

Ask question

All categories

3 years ago

10

7. Nancy has a mass of 60 kg and sits on the very end of a 3.00 m long plank pivoted in the middle. How much torque must her co-

worker provide on the other end of the plank in order to keep Nancy from falling on the ground?

1 answer:

netineya [11]3 years ago

6 0

Answer:

Torque = 882Nm

Explanation:

Torque = Mg×distance

But plank's is pivoted ,therefore distance=3/2=1.5m

Mass of Nancy=60jg

Acceleration due to gravity, g=9.8m/s^2

Torque= 60×9.8×1.5

Torque= 882Nm

You might be interested in

A ball is dropped from rest on a cliff what is the speed of the ball 5 seconds later

diamong [38]

Answer:

The velocity of the ball after 5 seconds will be 49 m/s

Explanation:

<em>v = final velocity</em>

<em>u = initial velocity</em>

<em>g = acceleration due to gravity</em>

<em>t = time</em>

Initial velocity of the ball = 0 (As the ball is dropped from rest )

Acceleration due to gravity = 9.8 m/s

Time taken = 5 sec

As the acceleration due to gravity is constant in both the cases we can use the equations of motion in order to solve this question

Part I :- As we already know the values of u,g,ant t we can use the first equation of motion in order to find v

Part II :- As we know the values of u, t , g we can use the second equation of motion in order to find s.

Velocity of the ball after 5 seconds

Distance covered by the ball in 5 sec

4 0

2 years ago

"A uniform cylinder of mass M and radius R is rolling without slipping. The velocity of its center of mass is v. What is the cyl

Goshia [24]

Answer:

Explanation:

Given

mass of cylinder is M

radius R

velocity of center of mass is v

As there is no slipping therefore cylinder will rotate as well as translate

Moment of inertia of cylinder $I=\frac{MR^2}{2}$

Kinetic Energy of cylinder $K.E.=\frac{1}{2}Mv^2$

Rotational energy $R.E.=\frac{1}{2}I\omega ^2$

for rolling

$v=\omega \times r$

where $\omega =angular\ velocity\ of\ cylinder$

$R.E.=\frac{1}{2}\times \frac{MR^2}{2}\times (\frac{v}{R})^2=\frac{1}{4}Mv^2$

Total kinetic Energy $=\frac{1}{2}Mv^2+\frac{1}{4}Mv^2=\frac{3}{4}Mv^2$

6 0

2 years ago

Given vectors D (3.00 m, 315 degrees wrt x-axis) and E (4.50 m, 53.0 degrees wrt x-axis), find the resultant R= D + E. (a) Write

Eva8 [605]

Answer:

R = ( 4.831 m , 1.469 m )

Magnitude of R = 5.049 m

Direction of R relative to the x axis= 16°54'33'

Explanation:

Knowing the magnitude and directions relative to the x axis, we can find the Cartesian representation of the vectors using the formula

$\vec{A}= | \vec{A} | \ ( \ cos(\theta) \ , \ sin (\theta) \ )$

where $| \vec{A} |$ its the magnitude and θ.

So, for our vectors, we will have:

$\vec{D}= 3.00 m \ ( \ cos(315) \ , \ sin (315) \ )$

$\vec{D}= ( 2.121 m , -2.121 m )$

and

$\vec{E}= 4.50 m \ ( \ cos(53.0) \ , \ sin (53.0) \ )$

$\vec{E}= ( 2.71 m , 3.59 m )$

Now, we can take the sum of the vectors

$\vec{R} = \vec{D} + \vec{E}$

$\vec{R} = ( 2.121 \ m , -2.121 \ m ) + ( 2.71 \ m , 3.59 \ m )$

$\vec{R} = ( 2.121 \ m + 2.71 \ m , -2.121 \ m + 3.59 \ m )$

$\vec{R} = ( 4.831 \ m , 1.469 \ m )$

This is R in Cartesian representation, now, to find the magnitude we can use the Pythagorean theorem

$|\vec{R}| = \sqrt{R_x^2 + R_y^2}$

$|\vec{R}| = \sqrt{(4.831 m)^2 + (1.469 m)^2}$

$|\vec{R}| = \sqrt{23.338 m^2 + 2.158 m^2}$

$|\vec{R}| = \sqrt{25.496 m^2}$

$|\vec{R}| = 5.049 m$

To find the direction, we can use

$\theta = arctan(\frac{R_y}{R_x})$

$\theta = arctan(\frac{1.469 \ m}{4.831 \ m})$

$\theta = arctan(0.304)$

$\theta = 16\°54'33''$

As we are in the first quadrant, this is relative to the x axis.

3 0

3 years ago

Which of the following statements is/are true?Check all that apply.a. A conservative force permits a two-way conversion between

Eddi Din [679]

Answer:

a). A conservative force permits a two-way conversion between kinetic and potential energies.

TRUE

Because there is no energy loss in presence of conservative forces so energy conversion in two ways are possible.

b). A potential energy function can be specified for a conservative force.

TRUE

negative gradient of potential energy is equal to conservative force

$F = -\frac{dU}{dr}$

c). A non-conservative force permits a two-way conversion between kinetic and potential energies.

FALSE

here energy is lost against non-conservative forces

d). The work done by a conservative force depends on the path taken.

FALSE

work done by conservative force is independent of path

e). The work done by a non-conservative force depends on the path taken.

TRUE

work done by non conservative forces depends on path.

f). A potential energy function can be specified for a non-conservative force.

FALSE

It is not defined for non conservative forces

3 0

3 years ago

A ______ is a network that has all connected devices located in the same physical location.

Dafna11 [192]

<span>The answer is Local Area Network (LAN). Examples of LANs, are those in workplaces, libraries, and universities. The nodes are connected and share common resources over a WiFi, Ethernet network, Token rings, and etcetera. The opposite of LAN is a Wide Area Network (WAN) that covers a wide geographical area.</span>

3 0

3 years ago