The surface layer of the sun, just below the chromosphere

Which organisms play roles similar to organisms in water ecosystem

lina2011 [118]

Is there a multiple choice?

4 0

4 years ago

A block with a mass of 31.8 kg is pushed on a frictionless

OlgaM077 [116]

Answer: Total work done on the block is 3670.5 Joules.

Step by step:

Work done:

$W = F.d.\cos\theta$

With F the force, d the displacement, and theta the angle of action (which is 0 since the block is pushed along the direction of displacement, and cos 0 = 1)

$W = F.d$

Given:

F = 75 N

m = 31.8 kg

Final velocity $v_f = 15.3 \frac{m}{s}$

In order to calculate the Work we need to determine the displacement, or distance the block travels. We can use the information about F and m to first figure out the acceleration:

$F = ma\\\implies a=\frac{F}{m}=\frac{75 N }{31.8 kg}\approx 2.36 \frac{m}{s^2}\\$

Now we can determine the displacement from the following formula:

$d = \frac{1}{2}a^2+v_0t+d_0$

Here, the initial displacement is 0 and initial velocity is also 0 (at rest):

$d = \frac{1}{2}at^2\\$

Now we still have "t" as unknown. But we are given one more bit of information from which this can be determined:

$v_f = a\cdot t_f\\\implies t_f = \frac{v_f}{a} = \frac{15.2 \frac{m}{s}}{2.36 \frac{m}{s^2}}\approx 6.44 s$

(using vf as final velocity, and tf as final time)

So it takes about 6.44 seconds for the block to move. This allows us to finally calculate the displacement:

$d = \frac{1}{2}at^2=\frac{1}{2}2.36 \frac{m}{s^2}\cdot 6.44^2 s^2 \approx 48.94 m$

and the corresponding work:

$W = F\cdot d=75 N\cdot 48.94 m =3670.5J$

7 0

3 years ago

Five equal negative charges are uniformly spaced in a semicircular

balu736 [363]

Answer:

The direction is that of a 3rd quadrant angle

Explanation:

when you have 2 45 angles it equals to 90 then with the 90 we multiply by 2 due to the 2 adjacent angles equating to 180 which swings it to the 3rd quadrant angle

6 0

4 years ago

You make a telephone call from New York to a friend in London. Estimate how long it will take the electrical signal generated by

nadezda [96]

Answer:

a) t = 2 10⁻² s , t = 2.4 10-1 s

Explanation:

In this exercise they indicate the delay in two signals

a) A signal travels on an electrical cable, between New York and London.

The wave formed in this wire for the signal. This wave travels at the speed of light, c = 3 108 m / s, so the delay is very small

t = d / c

t = 6000 10³/3 10⁸