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3 years ago

If two identical trees are cut down, one with a hand saw, and one with an electric saw...

Physics

1 answer:

nataly862011 [7]3 years ago

4 0

The hand saw would involve more work because it takes more time and effort.

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The current that charges a capacitor transfers energy that is stored in the capacitor’s electric field. Consider a 2.0 μF capaci

lapo4ka [179]

Answer:

the capacitor voltage is V = 20 V

Explanation:

Given,

Capacitance of the capacitor = 2.0 μF

energy stored = 200 W

time (t) =2.0 μs

Capacitor voltage = ?

$\dfrac{dE}{dt}=200 W$

$E =200\times 2 \times 10^{-6}$

$E =400 \times 10^{-6}\ J$

we know,

$E = \dfrac{1}{2}CV^2$

$V =\sqrt{\dfrac{2E}{C}}$

$V =\sqrt{\dfrac{2\times 400 \times 10^{-6}}{2\times 10^{-6}}}$

$V =\sqrt{400}$

V = 20 V

so , the capacitor voltage is V = 20 V

7 0

2 years ago

A pail in a water well is hoisted by means of a frictionless winch, which consists of a spool and a hand crank. When Jill turns

Katena32 [7]

Answer:

166 W

Explanation:

Power is the rate at which work is done.

$\text{Power} = \dfrac{\text{Work done}}{\text{time}}$

The work done by Jill is the product of the weight of the pail and the height it moves.

The weight is the product of the mass and acceleration of gravity, g. Taking g as 9.81 m/s², the weight is

W = (6.90 kg)(9.81 m/s²) = 67.689 N

Work done = (67.689 N)(27.0 m) = 1827.603 J

Power = (1827.603 J) ÷ (11.0 s) = 166 W

4 0

3 years ago

A 0.2 kg block sliding on a horizontal table slows down from 25 m/s to 20 m/s. How much energy does the block lose due to fricti

Papessa [141]

Answer:

the kinetic energy lost due to friction is 22.5 J

Explanation:

Given;

mass of the block, m = 0.2 kg

initial velocity of the block, u = 25 m/s

final velocity of the block, v = 20 m/s

The kinetic energy lost due to friction is calculated as;

$\Delta K.E= K.E_f - K.E_i\\\\\Delta K.E= \frac{1}{2}mv^2 - \frac{1}{2}mu^2\\\\\Delta K.E= \frac{1}{2}m(v^2 -u^2)\\\\\Delta K.E= \frac{1}{2} \times 0.2 (20^2 - 25^2)\\\\\Delta K.E= -22.5 \ J$

Therefore, the kinetic energy lost due to friction is 22.5 J

7 0

2 years ago

Read 2 more answers

Complete this sentence. If the mass of object A is __________ than object B, then the weight of object A will be _______________

AfilCa [17]

Answer:

Complete this sentence. If the mass of object A is greater than object B, then the weight of object A will be heavier the weight of object B.

Explanation:

If the mass of Object A is more/greater than object B then it would be "heavier"

4 0

2 years ago

Read 2 more answers

Which of the following. Chemical represent the law of conservation of Matter?

vazorg [7]

Answer:

The answer is first one 1...

6 0

3 years ago