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3 years ago

A wagon with an initial velocity of 2 m/s and a mass of 60 kg, gets a push with 150 joules of

Physics

1 answer:

Aleks04 [339]3 years ago

7 0

Answer:

v_f = 3 m/s

Explanation:

From work energy theorem;

W = K_f - K_i

Where;

K_f is final kinetic energy

K_i is initial kinetic energy

W is work done

K_f = ½mv_f²

K_i = ½mv_i²

Where v_f and v_i are final and initial velocities respectively

Thus;

W = ½mv_f² - ½mv_i²

We are given;

W = 150 J

m = 60 kg

v_i = 2 m/s

Thus;

150 = ½×60(v_f² - 2²)

150 = 30(v_f² - 4)

(v_f² - 4) = 150/30

(v_f² - 4) = 5

v_f² = 5 + 4

v_f² = 9

v_f = √9

v_f = 3 m/s

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In this image of a pendulum, where is the lowest potential energy found?

uranmaximum [27]

Think about the formula for potential energy. (Surely you remember it):

Potential energy = (mass) x (acceleration of gravity) x (height)

-- The mass on the end of the pendulum doesn't change.

-- The acceleration of gravity doesn't change.

-- The only thing that changes is the height of the mass on the end.

So the potential energy is lowest when its height is the lowest.

That's position <em>B </em>.

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3 years ago

A block slides to a stop as it goes 47 m across a level floor in a time of 6.35 s. a) What was the initial velocity? b) What is

UNO [17]

Answer :

(a) The initial velocity is, 14.8 m/s

(b) The acceleration is, $-2.33m/s^2$

Explanation :

By the 1st equation of motion,

$v=u+at$ ...........(1)

where,

v = final velocity = 0 s

u = initial velocity

t = time = 6.35 s

a = acceleration

The equation 1 will be:

$0=u+a(6.35}$

$u=-6.35a$ ..........(2)

By the 2nd equation of motion,

$s=ut+\frac{1}{2}at^2$ ...........(3)

where,

s = distance = 47 m

Now substitute equation 2 in 3, we get:

$47=(-6.35a)\times (6.35)+\frac{1}{2}\times a\times (6.35)^2$

By solving the term, we get:

$a=-2.33m/s^2$

The acceleration is, $-2.33m/s^2$

Now we have to calculate the initial velocity.

Using equation 2, we gte:

$u=-6.35a$

$u=-6.35s\times (-2.33m/s^2)$

$u=14.8m/s$

The initial velocity is, 14.8 m/s

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3 years ago

Which of the following best describes the use of a renewable resource?

bulgar [2K]

C IS THE CORRECT ANSWER.

Hope this helps!

6 0

3 years ago

Read 2 more answers

Find the position vector of a particle that has the given acceleration and the specified initial velocity and position. a(t) = 1

kondor19780726 [428]

Answer:

Explanation:

Given

Acceleration $a(t)=14t\hat{i]+\sin (t)\hat{j}+\cos (2t)\hat{k}$ [/tex]

and $v(0)=\hat{i}$

$r(0)=\hat{j}$

we know $a=\frac{\mathrm{d} v}{\mathrm{d} t}$

$\int dv=\int adt$

$v(t)=\int (14t\hat{i}+\sin (t)\hat{j}+\cos (2t)\hat{k})dt$

$v(t)=7t^2\hat{i}-\cos t\hat{j}+\frac{\sin (2t)\hat{k}}{2}+c$

at $t=0$

$v(0)=0-1\cdot \hat{j}+0+c$

$c=\hat{i}+\hat{j}$

$v(t)=(7t^2+1)\hat{i}+(1-\cos t)\hat{j}+\frac{\sin (2t)\hat{k}}{2}$

and $\frac{\mathrm{d} r}{\mathrm{d} t}=v(t)$

$\int dr=\int vdt$

$r(t)=\int ((7t^2+1)\hat{i}+(1-\cos t)\hat{j}+\frac{\sin (2t)\hat{k}}{2})dt$

$r(t)=(\frac{7}{2}t^3+t)\hat{i}+(t-\sin (t))\hat{j}+\frac{1}{2}\times (-\frac{1}{2}\cos 2t)\hat{k}+c_2$

at $t=0$

$r(0)=\hat{j}$

$r(t)=(\frac{7}{3}t^3+t)\hat{i}+(1+t-\sin t)\hat{j}+\frac{1}{4}(1-\cos 2t)\hat{k}$

4 0

3 years ago

HELP!!!!!!!!!

WARRIOR [948]

I think it would be A
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A and C

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3 years ago