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2 years ago

an elevator suspended by a vertical cable is moving downward but slowing down. the tension in the cable must be:

Physics

1 answer:

vladimir1956 [14]2 years ago

6 0

Answer:

F = M a is the vector equation involved

F = T - M g are the forces acting on the elevator (scalar equation)

T - M g = M a

T = M (a + g) remember this a scalar

If a is slowing down then it must have a positive acceleration upwards

Therefor the tension in the cable must be greater than zero

When the tension increases to M g, a has increased to zero

For a to be zero, no acceleration, T = M g

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Convert 3402kgm/s to 20000Newtons

oee [108]

The 3,402 has units of kg-m/s. That's momentum. The 20,000 has units of Newtons. That's force. Momentum and force are different physical things, and you can't convert them from one to the other.

The best I can do for you is something like this:

Let's say you have a moving object with 3,402 kg-m/s of momentum, and you want to STOP it completely. You want to stand in front of it and push back on it, hard enough and for long enough to CHANGE its momentum from 3,402 kg-m/s to zero.

Also ... there's a limit to how hard you can push. The most force you can exert is 20,000 Newtons.

The amount you'll change its momentum is called the impulse you give it. The quantity of impulse is (force) x (length of time you push on it).

So you need to keep pushing it back for (T seconds) long enough so that

(20,000 Newtons of force) x (T seconds) = 3,402 kg-m/s of momentum .

Divide each side of that equation by (20,000 Newtons). Then it says:

(T seconds) = (3,402 kg-m/s) / (20,000 Newtons)

T = 0.1701 second

And that's how you provide just enough impulse to stop the flying object ... push on it with 20,000 Newtons of force for exactly 0.1701 second, and it loses all its momentum and falls out of the air onto the ground at your feet.

This story is the closest I can come to anything that looks like "convert"ing momentum into force.

3 0

2 years ago

A 120 resistor a 60 ohm resistor and a 40 ohm resistor are connected in parallel to a 120 volt power source. what is the current

larisa [96]

Answer:

6 A

Explanation:

First of all, we need to calculate the equivalent resistance of the circuit. The three resistors are connected in parallel, so their equivalent resistance is given by:

$\frac{1}{R_T}=\frac{1}{R_1}+\frac{1}{R_2}+\frac{1}{R_3}=\frac{1}{120 \Omega}+\frac{1}{60 \Omega}+\frac{1}{40 \Omega}=\frac{3+2+1}{120 \Omega}=\frac{6}{120 \Omega}\\R_T = \frac{120}{6} \Omega$

And now we can use Ohm's law to find the current in the circuit:

$V=R_T II=\frac{V}{R_T}=\frac{120 V}{\frac{120}{6}\Omega}=6 A$

6 0

3 years ago

20. The speed of Light is 3.0 x 108 m/s. Blue Light has a frequency of 6.11 x 1014 Hz. What is its wavelength?

Sladkaya [172]

Answer:

4.91 x 10⁻⁷ m

Explanation:

the applicable formula is

v = fλ

where

v = velocity (i.e speed) = given as 3.0 x 10⁸ m/s

f = frequency = given asw 6.11 x 10¹⁴

λ = wavelength

if we rearrange the equation and substitute the values given above,

v = fλ

λ = v/f

= 3.0 x 10⁸ / 6.11 x 10¹⁴

= 4.91 x 10⁻⁷ m

5 0

3 years ago

A tennis ball is shot vertically upward in an evacuated chamber inside a tower with an initial speed of 20.0 m/s at time t=0s. W

dalvyx [7]

Answer:

at the highest point of the path the acceleration of ball is same as acceleration due to gravity

Explanation:

At the highest point of the path of the ball the speed of the ball becomes zero as the acceleration due to gravity will decelerate the motion of ball due to which the speed of ball will keep on decreasing and finally it comes to rest

So here we will say that at the highest point of the path the speed of the ball comes to zero

now by the force diagram we can say that net force on the ball due to gravity is given by

$F_g = mg$

now the acceleration of ball is given as

$a = \frac{F_g}{m}$

$a = \frac{mg}{m} = g$

so at the highest point of the path the acceleration of ball is same as acceleration due to gravity

5 0

2 years ago

How did France and Spain use what they learned during the American revolution to benefit their own countries

alexgriva [62]

Spain declared war on Britain as an ally of France, itself an ally of the American colonies, and provided supplies and munitions to the American forces. Beginning in 1776, it jointly funded Roderigue Hortalez and Company, a trading company that provided critical military supplies.

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3 years ago