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3 years ago

5

A 10-meter rope is lying on the floor and has a mass force of 20 N. How much work is required to raise one end of the rope to a

height of 5 meters?

1 answer:

VMariaS [17]3 years ago

7 0

Answer:10N

Explanation: I think

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A coil has 400 turns and self-inductance 7.50 mH. The current in the coil varies with time according to i = 1680 mA2 cos [πt/(0.

zhannawk [14.2K]

Answer:

(a) 1.58 V

(b) 0.0126 Wb

(c) 0.0493 V

Solution:

As per the question:

No. of turns in the coil, N = 400 turns

Self Inductance of the coil, L = 7.50 mH = $7.50\times 10^{- 3}\ H$

Current in the coil, i = $1680cos[\frac{\pi t}{0.0250}]$ A

where

$i_{max} = 1680\ mA = 1.680\ A$

Now,

(a) To calculate the maximum emf:

We know that maximum emf induced in the coil is given by:

$e = \frac{Ldi}{dt}$

$e = L\frac{d}{dt}(1680)cos[\frac{\pi t}{0.0250}]$

$e = - 7.50\times 10^{- 3}\times \frac{\pi}{0.0250}\times \frac{d}{dt}(1680)sin[\frac{\pi t}{0.0250}]$

For maximum emf, $sin\theta$ should be maximum, i.e., 1

Now, the magnitude of the maximum emf is given by:

$|e| = 7.50\times 10^{- 3}\times 1680\times 10^{- 3}\times \frac{\pi}{0.0250} = 1.58\ V$

(b) To calculate the maximum average flux,we know that:

$\phi_{m, avg} = L\times i_{max} = 7.50\times 10^{- 3}\times 1.680 = 0.0126\ Wb$

(c) To calculate the magnitude of the induced emf at t = 0.0180 s:

$e = e_{o}sin{\pi t}{0.0250}$

$e = 7.50\times 10^{- 3}\times sin{\pi \times 0.0180}{0.0250} = 2.96\times 10^{- 4} =0.0493\ V$

7 0

3 years ago

A 30.0 kg dolphin decelerates from 12.0 to 7.00 m/s in 2.60 s to join another dolphin in play. What average force (in N) was exe

Crazy boy [7]

Answer:

Force is 57.69 N to the opposite direction of motion of dolphin.

Explanation:

We have force is the product of mass and acceleration.

That is

Force = Mass x Acceleration

F = ma

Mass of dolphin, m = 30 kg

We have equation of motion, v = u + at

Final velocity, v = 7 m/s

Initial velocity, u = 12 m/s

Time, t = 2.60 s

Substituting

7 = 12 + a x 2.6

a = -1.92 m/s²

Force, F = 30 x -1.92 = -57.69 N

So the force is 57.69 N to the opposite direction of motion of dolphin.

7 0

2 years ago

Guyz wqy-bdet-mby join m.e f.o.r f.u.n

sergey [27]

Answer:

What?

Explanation:

4 0

2 years ago

You throw a baseball directly upward at time ????=0 at an initial speed of 14.9 m/s. What is the maximum height the ball reaches

xeze [42]

Answer:

Maximum height, h = 11.32 meters

Explanation:

It is given that,

The baseball is thrown directly upward at time, t = 0

Initial speed of the baseball, u = 14.9 m/s

Ignoring the resistance in this case and using a = g = 9.8 m/s²

We have to find the maximum height the ball reaches above where it leaves your hand. Let the maximum height is h. Using third equation of motion as :

$v^2-u^2=2ah$

At maximum height, v = 0

and a = -g = -9.8 m/s²

$h=\dfrac{v^2-u^2}{2a}$

$h=\dfrac{0-(14.9\ m/s)^2}{2\times -9.8\ m/s^2}$

h = 11.32 meters

Hence, the maximum height of the baseball is 11.32 meters.

8 0

3 years ago

A soccer ball with a mass of 0.45 kg is rolling with a momentum of 9 kg*m/s, what is it's velocity?

Lelu [443]

Answer: 20 m/s

Explanation:

P = mv

since we're trying to find the velocity, you change the formula to v = P/m

v = ?

P = 9 kgm/s

m = 0.45 kg

v = 9 kgm/s / 0.45kg = 20 m/s

3 0

2 years ago