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2 years ago

Can someone help me?!!!!!

Physics

1 answer:

igor_vitrenko [27]2 years ago

6 0

Answer:

7 units, north

Explanation:

This is a problem of vector subtraction. We have:

- Vector A: magnitude 2 units, direction to the north

- Vector B: magnitude 5 units, direction to the south

If we take the north as positive direction, we can write

$A = +2\\B=-5$

Since we want to find $A-B$ (vector subtraction), we have to change the sign of B, so we find:

$A-B=+2-(-5))=+2+5=+7$

And the positive sign means the direction is north.

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A tradesman sharpens a knife by pushing it with a constant force against the rim of a grindstone. The 30-cm-diameter stone is sp

Lorico [155]

Answer:

a. 0.21 rad/s2

b. 2.205 N

Explanation:

We convert from rpm to rad/s knowing that each revolution has 2π radians and each minute is 60 seconds

200 rpm = 200 * 2π / 60 = 21 rad/s

180 rpm = 180 * 2π / 60 = 18.85 rad/s

r = d/2 = 30cm / 2 = 15 cm = 0.15 m

a)So if the angular speed decreases steadily (at a constant rate) from 21 rad/s to 18.85 rad/s within 10s then the angular acceleration is

$\alpha = \frac{\Delta \omega}{\Delta t} = \frac{21 - 18.85}{10} = 0.21 rad/s^2$

b) Assume the grind stone is a solid disk, its moment of inertia is

$I = mR^2/2$

Where m = 28 kg is the disk mass and R = 0.15 m is the radius of the disk.

$I = 28*0.15^2/2 = 0.315 kgm^2$

So the friction torque is

$T_f = I\alpha = 0.315*0.21 = 0.06615 Nm$

The friction force is

$F_f = T_f/R = 0.06615 / 0.15 = 0.441 N$

Since the friction coefficient is 0.2, we can calculate the normal force that is used to press the knife against the stone

$N = F_f/\mu = 0.441/0.2 = 2.205 N$

7 0

2 years ago

A future use of space stations may be to provide hospitals for severely burned persons. It is very painful for a badly burned pe

inessss [21]

Answer:

1.5min

Explanation:

To solve the problem it is necessary to take into account the concepts related to Period and Centripetal Acceleration.

By definition centripetal acceleration is given by

$a_c = \frac{V^2}{r}$

Where,

V = Tangencial velocity

r = radius

With our values we know that

$a_c = \frac{V^2}{r}$

$\frac{V^2}{r} = \frac{1}{10}g$

Therefore solving to find V, we have:

$V = \sqrt{\frac{1}{10}g*r}$

$V = \sqrt{\frac{9.81*200}{10}}$

$V = 14m/s$

For definition we know that the Time to complete are revolution is given by

$t = \frac{Perimeter}{Speed}$

$t = \frac{2\pi R}{V}$

$t = \frac{2\pi * 200}{14}$

$t = 1.5min$

6 0

2 years ago

14. Saeed is pulling a 6 kg heavy rock with an upward force of 40 N but does not succeed to lift it up. What is the magnitude of

NemiM [27]

Answer:

58.8 N

Explanation:

The normal force is calculated as equal to the perpendicular component of the gravitational force.

Thus; N = mg

We are given m = 6 kg

Thus;

N = 6 × 9.8

N = 58.8 N

Thus, magnitude of normal force on the rock = 58.8 N

6 0

2 years ago

PLS HELP THIS IS WORTH 180 PTS!!(PLUS I WILL MARK BRAINIEST IF SOMEONE ANSWERS CORRECTY FIRST)

vazorg [7]

$\qquad\qquad\huge\underline{{\sf Answer}}$

The correct choice is ~ A

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7 0

1 year ago

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You are viewing a read out of an oscilloscope that shows you when different voltages in a circuit maximize. If the period of the

Aleksandr-060686 [28]

Answer:

The time is $t = 0.02 \ s$

Explanation:

From the question we are told that

The period of the circuit is $T = 0.04$

Generally voltage maximization of the capacitor occurs during the voltage minimization of the inductor and vise versa

So the time between the voltage maximization of the capacitor and that of the inductor is mathematically represented as

$t = \frac{T}{2}$

=> $t = \frac{0.04}{2}$

=> $t = 0.02 \ s$

7 0

2 years ago