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Novosadov [1.4K]

3 years ago

13

In an emergency situation, firemen need to respond as quickly as possible. If a fireman is responding from the second floor, how

long will it take to slide down the 8 m pole to reach the truck bay?

1 answer:

rjkz [21]3 years ago

8 0

Answer:

4m/s

Explanation:

May be different considering how long the pole is and how heavy the firefighter is.

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During a chemical reaction, some substances are completely consumed while others my not be. What is the substance that is comple

LUCKY_DIMON [66]

Answer:

It is Limiting Reactant

Explanation:

5 0

3 years ago

A student rubs a rubber balloon on their hair for several seconds. The student then rubs a second rubber balloon on her hair for

erastovalidia [21]

Answer:

Option A

Explanation:

In this experiment, when balloon is rubbed on the chair electrons are transferred from the hair to the surface of the balloon thereby making balloon negatively charged and hair positively charged. When two negatively charged balloon are brought close to each other, they repel while when balloon is brought closer to the hair, they attract each other

Hence, option A is correct

7 0

3 years ago

A 910-kg object is released from rest at an altitude of 1200 km above the north pole of the Earth. If we ignore atmospheric fric

gayaneshka [121]

In order to develop this problem it is necessary to use the concepts related to the conservation of both potential cinematic as gravitational energy,

$KE = \fract{1}{2}mv^2$

$PE = GMm(\frac{1}{r_1}-(\frac{1}{r_2}))$

Where,

M = Mass of Earth

m = Mass of Object

v = Velocity

r = Radius

G = Gravitational universal constant

Our values are given as,

$m = 910 Kg$

$r_1 = 1200 + 6371 km = 7571km$

$r_2 = 6371 km,$

Replacing we have,

$\frac{1}{2} mv^2 = -GMm(\frac{1}{r_1}-\frac{1}{r_2})$

$v^2 = -2GM(\frac{1}{r_1}-\frac{1}{r_2})$

$v^2 = -2*(6.673 *10^-11)(5.98 *10^24) (\frac{1}{(7.571 *10^6)} -\frac{1}{(6.371 *10^6)})$

$v = 4456 m/s$

Therefore the speed of the object when striking the surface of earth is 4456 m/s

3 0

4 years ago

A flat coil of wire consisting of 20 turns, each with an area of 50 cm2, is positioned perpendicularly to a uniform magnetic fie

Scilla [17]

Answer:

Induced current, I = 0.5 A

Explanation:

It is given that,

number of turns, N = 20

Area of wire, $A=50\ cm^2=0.005\ m^2$

Initial magnetic field, $B_i=2\ T$

Final magnetic field, $B_f=6\ T$

Time taken, t = 2 s

Resistance of the coil, R = 0.4 ohms

We know that due to change in magnetic field and emf will be induced in the coil. Its formula is given by :

$\epsilon=\dfrac{-d\phi}{dt}$

Where

$\phi=BA$

$\epsilon=\dfrac{-d(NBA)}{dt}$

$\epsilon=NA\dfrac{B_f-B_i}{t}$

$\epsilon=20\times 0.005\times \dfrac{6-2}{2}$

$\epsilon=0.2\ V$

Let I is the induced current in the wire. It can be calculated using Ohm's law as :

$\epsilon=I\times R$

$I=\dfrac{\epsilon}{R}$

$I=\dfrac{0.2}{0.4}$

I = 0.5 A

So, the magnitude of the induced current in the coil is 0.5 A. Hence, this is the required solution.

5 0

3 years ago

A 350 gram mass is tied to a string and spin in a horizontal circle with a radius of 11.0cm.The speed of the mass is held consta

SSSSS [86.1K]

Explanation:

a) The angular speed omega is given defined as

omega = #rev/period = 1 rev/(0.6 s) = 1.7 rev/s

= (1.7 rev/s)×(2pi/rev) = 10.5 rad/s

b) v = (omega)×r

= (10.5 rad/s)(0.110 m)

= 1.16 m/s

7 0

3 years ago