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Y_Kistochka [10]
3 years ago
13

How much work (in j) must be done to lift a stack of bricks, which has a mass of 400 kg, from the ground to a height of 3 m? (g

= 10 m/s2)?
Physics
1 answer:
svetoff [14.1K]3 years ago
6 0
Given: Mass m = 400 Kg;   Height h = 3 m;     g = 10 m/s²

Required:  Work = ?

Formula: Work = Force x distance  F = ma    a = g    F = mg

W = fd

W = mgh

W = (400 Kg)(10 m/s²)( 3 m)

W = 12,000 Kg.m²/s²

W = 12,000 J

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A mass of 0.40 kg is suspended on a spring which then stretches 10 cm. The mass is then removed and a second mass is placed on t
Vanyuwa [196]

Answer:

 x' = 1.01 m

Explanation:

given,

mass suspended on the spring, m = 0.40 Kg

stretches to distance, x = 10 cm  = 0. 1 m

now,

we know

m g = k x

where k is spring constant

0.4 x 9.8 = k x 0.1

  k = 39.2 N/m

now, when second mass is attached to the spring work is equal to 20 J

work done by the spring is equal to

W = \dfrac{1}{2}kx'^2

20= \dfrac{1}{2}\times 39.2\times x'^2

 x'² = 1.0204

 x' = 1.01 m

hence, the spring is stretched to 1.01 m from the second mass.

 

7 0
3 years ago
The use of force to move an object is BLANK .
pashok25 [27]

Answer:

Work

Explanation:

The use of force to move an object is the definition of "work" in physics.

5 0
3 years ago
Read 2 more answers
The electric force between two charges A. increases with distance between the charges B. increases if either one of charges gets
beks73 [17]

Answer:

Option (A) , (b) and (d) are correct option

Explanation:

According to Coulomb's law electric force between two charges is given by

F=\frac{1}{4\pi \epsilon _0}\frac{q_1q_2}{r^2}

From the relation we can say that force is directly proportional to magnitude of charges and inversely proportional to distance between them '

So if we increase the distance then force will decrease

Increase if any of the charge get larger

If force is attractive then both the charge will be of different sign and is force is repulsive then both the charges of same sign

From above conclusion we can say that (a), (b) and (d) are correct option

6 0
3 years ago
A middle-A tuning fork vibrates with a frequency f of 440 hertz (cycles per second). You strike a middle-A tuning fork with a fo
jeyben [28]

Answer:

P = 5sin(880πt)

Explanation:

We write the pressure in the form P = Asin2πft where A = amplitude of pressure, f = frequency of vibration and t = time.

Now, striking the middle-A tuning fork with a force that produces a maximum pressure of 5 pascals implies A = 5 Pa.

Also, the frequency of vibration is 440 hertz. So, f = 440Hz

Thus, P = Asin2πft

P = 5sin2π(440)t

P = 5sin(880πt)

3 0
3 years ago
How are magnetic poles and electrical charges similar? A. Their same forces repel each other, and their opposite forces attract
melomori [17]

Answer:

A. Their same forces repel each other, and their opposite forces attract each other.

Explanation:

As we know by the property of electric charge that similar charges repel each other and opposite charges attracts each other

So here we have similar situation in magnets also

Two similar poles or like poles of magnet i.e. North - North poles or South - South poles always repel each other

And also we can see that opposite poles of magnet each other i.e. North pole and south pole always attract each other.

SO here correct answer is

A. Their same forces repel each other, and their opposite forces attract each other.

8 0
3 years ago
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