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rosijanka [135]
2 years ago
14

An object has a kinetic energy of 810 J after falling a certain distance. If the mass of the object is 20kg, what is the speed o

f the object at this time?
I need the equation and answer please!
Physics
1 answer:
Darina [25.2K]2 years ago
6 0
Don't let the "falling" confuse you. A moving object's kinetic energy is

K.E. = 1/2 (mass) (speed^2)

no matter what direction it's moving, or why.

In this problem, you know the KE and the mass, so

810 J = 1/2 (20 kg) (speed^2).

I think you can probably find the speed now.
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On a snowy day, max (mass = 15 kg) pulls his little sister maya in a sled (combined mass = 20 kg) through the slippery snow. max
sesenic [268]

Work done by a given force is given by

W = F.d

here on sled two forces will do work

1. Applied force by Max

2. Frictional force due to ground

Now by force diagram of sled we can see the angle of force and displacement

work done by Max = W_1 = Fdcos\theta

W_1 = 12*5cos15

W_1 = 57.96 J

Now similarly work done by frictional force

W_2 = Fdcos\theta

W_2 = 4*5cos180

W_2= -20 J

Now total work done on sled

W_{net}= W_1 + W2

W_{net} = 57.96 - 20 = 37.96 J

7 0
3 years ago
A 8.4-mH inductor carries a current I = Imaxsin ωt, with Imax = 4.00 A and f = ω/2π = 60.0 Hz. What is the self-induced emf as a
Aleks04 [339]

Answer:

E= -3.166 cosωt   V

Explanation:

Given that

I = Imax sinωt

L= 8.4 m H

Imax= 4 A

f = ω/2π = 60.0 Hz

ω = 120π  rad/s

We know that self induce E given as

E=-L\dfrac{dI}{dt}

\dfrac{dI}{dt}= Imax \ \omega\ cos\omega t

E=-L\times Imax \ \omega\ cos\omega t

E=-8.4\times 120\times \pi \ cos\omega t

E= -3166.72 cosωt  m V

E= -3.166 cosωt   V

This is the induce emf.

3 0
2 years ago
12) Water flows through a horizontal pipe of cross-sectional area 10.0 cm2 at a pressure of 0.250 atm with a flow rate is 1.00 L
masha68 [24]

Answer:

The pressure after passing the valve is 23,8 [Kpa] ( 0,234 atm) and the pressure drop is about 1,53 [Kpa]

Explanation:

We need to use the formula of bernoulli, in the attached image we can see the fluid throw the pipe, we also can calculate the velocity inside the pipe using the flow rate and the cross sectional area.

For this case, we don't use the elevation difference and therefore those terms can be cancelled.

When the area has reduced the velocity of the fluid is increased but there is a drop pressure through the valve.

5 0
3 years ago
Help please !
Yuri [45]

Answer:

1) Adenine (A)   2. Uracil (U)   4) Cytosine (C)

Explanation:

"RNA consists of four nitrogenous bases: adenine, cytosine, uracil, and guanine."

5 0
2 years ago
The contact force that acts on objects in a liquid or gas and allows objects to float is called
Harrizon [31]
<span>The contact force that acts on objects in a liquid or gas and allows objects to float is called    </span>Buoyancy.
8 0
3 years ago
Read 2 more answers
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