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2 years ago

How much work in joules must be done to stop a 920-kg car traveling at 90 km/h?

Physics

1 answer:

tankabanditka [31]2 years ago

3 0

Answer:

Work done, W = −287500 Joules

Explanation:

It is given that,

Mass of the car, m = 920 kg

The car is travelling at a speed of, u = 90 km/h = 25 m/s

We need to find the amount of work must be done to stop this car. The final velocity of the car, v = 0

Work done is also defined as the change in kinetic energy of an object i.e.

$W=\Delta K$

$W=\dfrac{1}{2}m(v^2-u^2)$

$W=\dfrac{1}{2}\times 920\ kg(0-(25\ m/s)^2)$

W = −287500 Joules

Negative sign shows the work done is done is opposite direction.

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2 years ago

How long does it take to travel a distance of 672km at a speed of 95km/h?

Brilliant_brown [7]

Answer:

7.07 hours

Explanation:

divide the distance by the speed

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2 years ago

Could a mixture be made up of only elements and no compounds?

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3 years ago

Read 2 more answers

Alternating Current In Europe, the voltage of the alternating current coming through an electrical outlet can be modeled by the

stealth61 [152]

Answer:

$\frac{50}{\pi }$ Hz

Explanation:

In alternating current (AC) circuits, voltage (V) oscillates in a sine wave pattern and has a general equation as a function of time (t) as follows;

V(t) = V sin (ωt + Ф) -----------------(i)

Where;

V = amplitude value of the voltage

ω = angular frequency = 2 π f [f = cyclic frequency or simply, frequency]

Ф = phase difference between voltage and current.

Now,

From the question,

V(t) = 230 sin (100t) ---------------(ii)

By comparing equations (i) and (ii) the following holds;

V = 230

ω = 100

Ф = 0

But;

ω = 2 π f = 100

2 π f = 100 [divide both sides by 2]

π f = 50

f = $\frac{50}{\pi }$ Hz

Therefore, the frequency of the voltage is $\frac{50}{\pi }$ Hz

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2 years ago

Carol drops a stone in a mine shaft 122.5 metres deep.How

Verizon [17]

Answer:

T = 5.36 s

Explanation:

given,

depth of the mine shaft = 122.5 m

speed of the sound = 340 m/s

time taken = ?

time taken by the stone to reach at the bottom

using equation of motion

$s = u t + \dfrac{1}{2}gt^2$

initial speed , u = 0 m/s

$t = \sqrt{\dfrac{2s}{g}}$

$t = \sqrt{\dfrac{2\times 122.5}{9.8}}$

t = 5 s

time taken by the sound to travel

d =v x t

$t = \dfrac{d}{v}$

$t = \dfrac{122.5}{340}$

t = 0.36 s

total time taken for the sound to reach carol after dropping the stone

T = 5 + 0.36

T = 5.36 s

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3 years ago