All categories

3 years ago

True / False

Physics

2 answers:

devlian [24]3 years ago

8 0

1. True
2. True
3. True
4. True
5. False
6. False
7. True

DaniilM [7]3 years ago

7 0

Answer:

1. True

2. False

3. True

4. True

5. True

6. True

7. True

You might be interested in

A current flowing through you of more than 5 ma is considered dangerous. Why do we see warnings about high voltage, rather than

svet-max [94.6K]

Answer:

V = 500 volts

I = 50 nA

Explanation:

We usually see 'high voltage' sign rather than 'high current' this is due to the fact that the amount of current depends upon the resistance of the body,

The relation of voltage, current and resistance is given by Ohm's law,

V = IR

I = V/R

As you can see, current and resistance are inversely related, the lower the resistance of the body, the higher will be the current flowing through the body.

What voltages are dangerous even if the skin is dry?

A dry human body has a resistance of approximately 100 kΩ and it gets reduced if the body is wet.

For a current of 5 mA, the corresponding voltage is,

V = 0.005*100,000

V = 500 volts

Therefore, for a dry human body, a voltage of 500 volts would be dangerous.

If voltage differences that are observed are about 0.5 mV, and the resistance of the skin is about 10 kΩ, what size currents are involved?

I = V/R

I = 0.0005/10,000

I = 50×10⁻⁹ A

I = 50 nA

Therefore, a current of 50 nA would be flowing through the EEG.

8 0

3 years ago

A man is dragging a trunk up the loading ramp of a mover's

FinnZ [79.3K]

Answer:

Horizontal component = 241 N

Vertical component = 287 N

Explanation:

Given:

Force = F = 375 N

Referring to diagram attached, the force F is making an angle

theta = 20+30 = 50 with the horizontal.

Horizontal component = F*cos(theta) = 375*0.64278 = 241 N

Vertical component = F*sin(theta) = 375*0.76604 = 287 N

4 0

3 years ago

A 1.4kg block and a 2.7kg block are attached to opposite ends of a light rope. The rope hangs over a solid, frictionless pulley

leonid [27]

Answer:

$32.67 m/s^2$

Explanation:

27 cm = 0.27 m

As the blocks are hanging on 2 sides of the pulley, their difference in mass would generate a net force toward the heavier side:

Let g = 9.81 m/s2

F = g(2.7 - 1.4) = 9.81*1.3 = 12.753 N

This force would generate a torque at 0.27 m moment arm

T = F*r = 12.753*0.27 = 3.44 Nm

The moment of inertia of the solid disk:

$I = mR^2/2$

Where m = 0.78 kg is the disk mass and R = 0.27 m is the radius of the disk.

$I = 0.780*27^2/2 = 0.028431 kgm^2$

So the angular acceleration of the torque is

$\alpha = T/I = 3.44 / 0.028431 = 121 rad/s^2$

So the linear acceleration is its angular component times radius

$a = \alpha r = 121 * 0.27 = 32.67 m/s^2$

3 0

3 years ago

If a gun is sighted to hit targets that are at the same height as the gun and 95 m away, how low will the bullet hit if aimed di

Elina [12.6K]

Horizontal distance between the bullet and the target (s) = 195 m

Horizontal velocity of the bullet (u) = 275 m/s

Time taken to cover the horizontal distance = $\frac{Distance}{velocity}$

Time taken (t) = $\frac{195}{275}$

t = 0.709 s

Now, in the vertical direction:

Initial velocity (u) = 0 m/s

Let the depth covered be h.

Time taken (T) = 0.709 s

Acceleration due to gravity (g) = 9.8 m/s^2

Now, using the seconds equation of motion:

$h = ut + \frac{1}{2}at^2$

$h = 0 +\frac{1}{2}\times 9.8 \times 0.709^2$

h = 2.463 meters

Hence, the bullet will hit 2.463 meters below the target.

3 0

3 years ago

If mass increases - Force of gravity increases <br><br> A. True<br><br> B.False

rewona [7]

The answer is True.

5 0

3 years ago