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3 years ago

A particle moves in a straight line. Its speed(v)

Physics

1 answer:

Alina [70]3 years ago

3 0

Answer:

$6v_0$

Explanation:

The speed of the particle increases linearly with time, so we can write it as

$v(t) = kt+v_0$

where k is the a certain constant of proportionality and $v_0$ is the initial speed.

We also know that at t = 4 s, the speed is $v=2v_0$ , so we can use this information to find k:

$v(4) = 4k+v_0 = 2v_0 \rightarrow k = \frac{v_0}{4}$

So the complete expression of v(t) is

$v(t) = \frac{v_0}{4}t+v_0 = v_0 (\frac{t}{4}+1)$

Now we integrate the quantity $v(t)$ , and we find:

$\int {v(t)} \, dt =\int (\frac{v_0}{4}t+v_0) \, dt =\frac{v_0}{8}t^2 + v_0 t$

Substituting the limit of integration t = 4, we find:

$\frac{v_0}{8}4^2 + 4v_0 =2v_0+4v_0 = 6v_0$

And substituting t = 0, we find 0. So, the result of the integration from 0 to 4 is

$6v_0$

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A spring has a natural length of 0.5 m and was stretched by 0.02 m. if the spring had a resultant energy of 0.5 j what is the sp

Anna71 [15]

$\textbf{2500 }\dfrac{\textbf{kg}}{\textbf{s}^{\textbf{2}}}$

Explanation:

Natural length of a spring is $0.5\text{ }m$ . The spring is streched by $0.02\text{ }m$ . The resultant energy of the spring is $0.5\text{ }J$ .

The potential energy of an ideal spring with spring constant $k$ and elongation $x$ is given by $\dfrac{1}{2}kx^{2}$ .

So, in the current problem, the natural length of the spring is not required to find the spring constant $k$ .

$\text{Potential Energy in the spring = }\dfrac{1}{2}kx^{2}\\0.5\text{ }J\text{ }=\text{ }\dfrac{1}{2}k(0.02\text{ }m)^{2}\\k\times0.0004\text{ }m^{2}\text{ }=\text{ }1\text{ }J\text{ }=\text{ }1\text{ }kg\frac{m^{2}}{s^{2}}\\k\text{ }=\text{ }\dfrac{1\text{ }kg\dfrac{m^{2}}{s^{2}}}{0.0004\text{ }m^{2}}\text{ }=\text{ }2500\text{ }\frac{kg}{s^{2}}$

∴ The spring constant of the spring = $2500\text{ }\frac{kg}{s^{2}}$

4 0

3 years ago

1.Convert 340 cm into m *(answer=0.34m)

Nataly [62]

Answer:

1.for the first one 100centimeters make 1 meter therefore

100cm-1m

340cm-x

340/100

=3.4

the answer is supposed to be 3.4, maybe there's a mistake with the question or the answer

2.the weight of a body is given by the formula

mass×gravity,in this case the mass is 75kg and the gravity is 9.8

weight=75×9.8

=735N

3.for this one the mass of a body is given by the formula

mass=weight/gravity

=420/9.8

=42.8kg

I hope this helps

4 0

3 years ago

"Without forces there can be no movement"- Do you agree with this statement? Why or Why not?

myrzilka [38]

Answer: Yes.

Explanation: It is clearly stated in Newton’s first law of physics that an object will not change its motion unless a force acts on.

6 0

3 years ago

A delivery truck leaves a warehouse and travels 3.20 km east. The truck makes a right turn and travels 2.45 km south to arrive a

boyakko [2]

Explanation:

It is given that,

Displacement of the delivery truck, $d_1=3.2\ km$ (due east)

Then the truck moves, $d_2=2.45\ km$ (due south)

Let d is the magnitude of the truck’s displacement from the warehouse. The net displacement is given by :

$d=\sqrt{d_1^2+d_2^2}$

$d=\sqrt{3.2^2+2.45^2}$

d = 4.03 km

Let $\theta$ is the direction of the truck’s displacement from the warehouse from south of east.

$\theta=tan^{-1}(\dfrac{2.45}{3.2})$

$\theta=37.43^{\circ}$

So, the magnitude and direction of the truck’s displacement from the warehouse is 4.03 km, 37.4° south of east.

8 0

3 years ago

Which quantities indicate a direction and a magnitude? Check all that apply.

Korvikt [17]

Answer:

Vector, in physics, a quantity that has both magnitude and direction. It is typically represented by an arrow whose direction is the same as that of the quantity and whose length is proportional to the quantity's magnitude. Although a vector has magnitude and direction, it does not have position.

Explanation:

The only thing I found in my notes for this question was this although it isn't in your choices, I just hope this helps you and hope you get it right!

7 0

3 years ago