What is the average velocity of a car that travels 50 kilometers due west in 0.50 hour?

it takes 90 j of work to stretch a spring 0.2 m from its equilibrium position. How muc work is needed to stretch it an additiona

Vinvika [58]

Work needed: 720 J

Explanation:

The work needed to stretch a spring is equal to the elastic potential energy stored in the spring when it is stretched, which is given by

$E=\frac{1}{2}kx^2$

where

k is the spring constant

x is the stretching of the spring from the equilibrium position

In this problem, we have

E = 90 J (work done to stretch the spring)

x = 0.2 m (stretching)

Therefore, the spring constant is

$k=\frac{2E}{x^2}=\frac{2(90)}{(0.2)^2}=4500 N/m$

Now we can find what is the work done to stretch the spring by an additional 0.4 m, that means to a total displacement of

x = 0.2 + 0.4 = 0.6 m

Substituting,

$E'=\frac{1}{2}kx^2=\frac{1}{2}(4500)(0.6)^2=810 J$

Therefore, the additional work needed is

$\Delta E=E'-E=810-90=720 J$

Learn more about work:

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7 0

3 years ago

You drop a rock off a bridge. The rock's height, h (in feet above the water), after t seconds is modeled by h = – 16 t2 + 541. W

marin [14]

h ( t) = h(1 sec) = -16t^2 + 541

so h (2 sec) = -16*(2)^2 + 541 = -64 + 541 = 477 ft

Therefore, the height of the rock after 2 seconds is 477 feet.

I hope my answer has come to your help. Thank you for posting your question here in Brainly.

5 0

3 years ago

The velocity of blood flow is ________. A) in direct proportion to the total cross-sectional area of the blood vessels B) slower

Leto [7]

Answer:

Option (D)

Explanation:

The velocity at which blood flows in the blood vessels is inversely proportional to the total cross-sectional area of the blood vessels present in the body. This means that if the cross sectional area of the vessels low, then there will be high rate of blood flow, and vice versa. This blood flow is minimum in the case of capillaries, where it gets enough time for the exchanging of essential nutrients as well as gases.

Thus, the correct answer is option (D).

5 0

3 years ago

You can comfortably hold your fingers close beside a candle flame, but not very close above the flame. why? challenge (optional)

Inessa05 [86]

The candle flame releases hot gases, which directly go in upwards directions. Due to which the air near the flame of the candle is very hot and dense. The particles along with vapour move up. And since the sideways, the air is not very dense and hot, we are able to hold the candle. In anti-gravity region, there will be no density differences and also, the convection process wont occur. So, the candle quickly snuffs off.

6 0

3 years ago

Read 2 more answers

How many electrons would it take to equal the mass of a proton? Use two significant figures.

mezya [45]

How many electrons would it take to equal the mass of a proton:
Here's one way of finding the value of it:
=> number of electrons is equivalent to 1 proton.
Let's have an example.
1.6726*10 -24g
_______________
1 proton
______________
9.109*10- ^28g
_______________
1 electron

Based on the given example above, the electrons is 1 839 per 1 proton.
It's about 1800 electrons/proton.

5 0

3 years ago