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Lubov Fominskaja [6]
3 years ago
9

20 kg object travels 28 meter and stops. coefficient friction= 0.085 how much work was done by friction?

Physics
1 answer:
Tresset [83]3 years ago
7 0
Assuming it is on a horizontal surface:
friction = μR
R = 20g (g is gravity 9.81)
so Friction = 0.085 x 20g
Work done is force x distance 
so Work done = 0.085 x 20g x 28
 = 466.956 J

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A single-turn square loop carries a current of 16 A . The loop is 15 cm on a side and has a mass of 3.8×10^−2kg . Initially the
DiKsa [7]

Answer:

The minimum magnetic field is 0.078 T.

Explanation:

Given that,

Current = 16 A

Side = 15 cm

Mass m= 3.8\times10^{-2}\ kg

Mass each segment in given square loop is

m=\dfrac{3.8\times10^{-2}}{4}

We need to calculate the torque due to gravity

Using formula of torque

\tau_{g}=2mg(\dfrac{L}{2})+mgL

\tau_{g}=2mgL

The torque due to magnetic field

\tau_{B}=FL

\tau_{B}=BIL^2

The equilibrium condition

\tau_{B}=\tau_{g}

Put the value into the formula

BIL^2=2mgL

B=\dfrac{2mgL}{IL^2}

B=\dfrac{2mg}{IL}

Put the value into the formula

B=\dfrac{2\times\dfrac{3.8\times10^{-2}}{4}\times9.8}{16\times15\times10^{-2}}

B=0.078\ T

Hence, The minimum magnetic field is 0.078 T.

7 0
3 years ago
An electron, moving south, enters a magnetic field of certain strength. Because of this field the electron curves upward. What i
e-lub [12.9K]

Answer: The magnetic field points to the west.

Explanation:

If we take the plane as:

North = positive y-axis

East = positive x-axis.

We have that the electron is moving south, so the velocity of the electron can be written in vector form as:

V = (0, -v, 0)

Now, when the electron interacts with the magnetic field, the electron moves upwards.

We know that the interaction between an electron and a magnetic field is:

F = q*VxB

So we have that this force acts on the z-direction.

Now, to solve this we can use the righ hand rule.

First, we point wit our hand to the direction of the velocity (negative y-axis) now, we want that our thumb points up (the direction of the force) so the side where our palm faces is the direction of the field B.

But, remember that an electron has a negative charge, so the actual equation is:

F = -q*VxB

So the magnetic field actually points in the opposite direction of our palm, to the west.

Now, we can also solve it mathematically as:

F = (0, 0, f) = -q*(0, -v,0)x(a, b, c)

where B = (a, b, c) is the vector of the magnetic field.

     (0, 0, f) = -q*(-v*b -0, -0 + 0, 0 -(- a*v)) = -q*(-v*b, 0, a*v)

then we have that b must be equal to zero, and that:

f = -q*a*v

and f is positive, then we have:

a = -(f/q*v)

then the vector of the magnetic field is:

B = (-(f/q*v), 0, 0)

so it points in the negative x-axis, that is the West, as we found earlier.

4 0
3 years ago
This object is located 13.0 cm to the left of the lens and the image forms at 20.8 cm to the right of the lens.
Alina [70]

Answer:

0.125 cm

Explanation:

1/f = 1/d¡ + 1/d。

Find the focal point

(13.0^-1 + 20.8^-1) = 0.125 m

Focal point = 0.125 m  

6 0
2 years ago
Read 2 more answers
How do you find the weight of an object when given the mass and acceleration?
murzikaleks [220]

Weight of an object is given by the formula W = m x g , where

m : mass of the object

g : gravitational acceleration

It is <u>independent of the horizontal </u><u>acceleration</u>.  

<h3>What do we mean by weight of an object?</h3>

Weight is a gauge of how strongly gravity is<u> pulling something down.</u> It is dependent on the object's mass, or how much matter it consists of. It also depends on the <u>object's uniformly distributed</u> downward acceleration caused by gravity.

This equation can be used to express weight:

 W = m x g

<h3>What is the difference between weight and mass of an object?</h3>

In everyday speech, the phrases "mass" and "weight" are frequently used interchangeably; nevertheless, the two concepts don't have the same meaning. In contrast to weight, which is a <u>measurement of</u> how the <u>force</u> of gravity works upon a mass, mass is the <u>amount of substance</u> in a material.

To learn more about gravity and acceleration :

brainly.com/question/13860566

#SPJ4

3 0
1 year ago
9. According to statistical theory, 68% of your measurements of time should fall within the range of and of therefore about 3 of
Nady [450]

Answer:

Yes

Explanation:

Yes, this is a random error generating because of statistical constraint. We only have finite number of data points. As per this, if we plot our observation we will get a gaussian (inverse bell ) shaped curve with mean equal to central value.

5 0
2 years ago
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