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2 years ago

14

6. A girl pushes her little brother on his sled with a force of 300 N for 750 m.

1 answer:

Oduvanchick [21]2 years ago

5 0

w=225000 J

E=225000 J

P=9000 W

P=22500 W

Ew=Fd=E

P=E/t

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Monica [59]

Answer:

im pretty sure it is C. Insulation

Explanation:

because it says reduced, and basically ur insulating the fire.

5 0

3 years ago

A 15 kg bucket of water is suspended by a very light ropewrapped around a solid uniform cylinder 0.300 m in diamter withmass 12.

matrenka [14]

Answer:

Part a)

$T = 42 N$

Part b)

$v_f = 11.8 m/s$

Part c)

$t = 1.7 s$

Part d)

$F = 159.7 N$

Explanation:

Part a)

While bucket is falling downwards we have force equation of the bucket given as

$mg - T = ma$

for uniform cylinder we will have

$TR = I\alpha$

so we have

$T = \frac{1}{2}MR^2(\frac{a}{R^2})$

$T = \frac{1}{2}Ma$

now we have

$mg = (\frac{M}{2} + m)a$

$a = \frac{mg}{(\frac{M}{2} + m)}$

$a = \frac{15 \times 9.81}{(6 + 15)}$

$a = 7 m/s^2$

now we have

$T = \frac{12 \times 7}{2}$

$T = 42 N$

Part b)

speed of the bucket can be found using kinematics

so we have

$v_f^2 - v_i^2 = 2 a d$

$v_f^2 - 0 = 2(7)(10)$

$v_f = 11.8 m/s$

Part c)

now in order to find the time of fall we can use another equation

$v_f - v_i = at$

$11.8 - 0 = 7 t$

$t = 1.7 s$

Part d)

as we know that cylinder is at rest and not moving downwards

so here we can use force balance

$F = T + Mg$

$F = 42 + (12 \times 9.81)$

$F = 159.7 N$

5 0

3 years ago

What is the average speed of a boy who jogs 250 meters in 110 seconds

Ede4ka [16]

2.27 mps repeating.

This is the last question ill ever answer here. Thanks for being the last.

8 0

3 years ago

Read 2 more answers

A wave with low energy will also have

Aliun [14]

Will also have low frequency

3 0

3 years ago

A cubic box has a 0.6 cubic decimetre side. Find the mass of air in the box in gram. (1 Liter of air has a mass of 1.3 g).

morpeh [17]

Answer:

The mass of air in the box is 0.78 grams.

Explanation:

A litre equals a cubic decimetre. By definition of density ( $\rho$ ), in grams per litre, we calculate the mass of air inside the cube ( $m$ ), in grams:

$m = \rho \cdot V$ (1)

Where $V$ is the volume occupied by air within the cube, in litres.

If we know that $V = 0.6\,L$ and $\rho = 1.3\,\frac{g}{L}$ , then the mass of air is:

$m = \left(1.3\,\frac{g}{L} \right)\cdot (0.6\,L)$

$m = 0.78\,g$

The mass of air in the box is 0.78 grams.

4 0

2 years ago