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3 years ago

Hansel pushes a 2 lb. box 5 feet in 20 seconds. How much work has he done?

1 answer:

8 0

Work = force x distance

You can see time doesn’t matter (if we were talking about power, which is the RATE at which work is performed, that would be a different story).

W = 2 x 5 = 10 foot-pounds of work

Foot-pounds are gross units. Better to work in SI units when you can!

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Problem:

Mars2501 [29]

I do have a couple ideas and tips that may help you win. I don’t know how the guidelines are set up so if the ideas won’t be helpful I apologize.

First off put some ice cubes in the container then sprinkle salt on them, The reaction will create an effect and be super cold.

Another idea would be to get some dry ice if you able to, This will freeze it solid within seconds.

The last idea combines the the first. Take a bowl and fill it with with water and ice (Make sure the bowl is insulated) add a small handful of salt into the bowl, Put your drink into the cooler and before shutting stir then well then close and wait for the amount of time left, Your should have a cold water bottle.

I hoped this helped you out and I hope you also win the contest.

8 0

3 years ago

If there is no oxygen in outer space, and, at the same time, oxygen must be present for fire, where does the sun come from?

victus00 [196]

The sun is a huge ball of gas held together by gravity.

It does not burn the way wood does, due to oxygen, but it gets energy by a process called nuclear fusion, where Hydrogen is converted to Helium.

The sun will cease to "burn" when it runs out of Hydrogen, but that has a long way to go.

3 0

3 years ago

Read 2 more answers

La ecuación de la posición de una esferita está dada por: r(t)=(2.Cos(πt) i-3.Sen(πt) j) (m) ¿Cuál es la velocidad de la esferit

katovenus [111]

Answer:

v = (-4.44 i^ + 6.66 j^ ) m/s, a_average =( 0 i^ -2π j^) m/s²

Explanation:

The expression left corresponds to an oscillatory movement (MAS), the speed is defined by

v = dr / dt

the function of position

r = 2 cos πt i^ + 3 sin πt j^

let us note that it is a movement in two dimensions

let's perform the derivative

v = -2π sin πt i^ + 3π cos πt j^

we evaluate this expression for t = 0.25 s, remember that the angle is in radians

v = -2π sin (π 0.25) i^ + 3π cos (π 0.25) j^

v = (-4.44 i^ + 6.66 j^ ) m/s

To calculate the mean acceleration we use the expression

a = ( $v_{f} - v_{o}$ ) / Δt

indicates that the time is the first 3 s

we look for the initial velocity t = 0 s

v₀ = 0 i ^ + 3π j ^

we look for the fine velocity, t = 3 s

v_f = - 2π sin (π 3) + 3π cos (π 3) j ^

v_f = 0 i ^ - 3π j ^

we calculate the average acceleration

Δt = (3 -0) = 3 s

a_average = (0-0) / 3 i ^ + (-3π - 3π) / 3

a_average = (0 i ^ -2π j ^ ) m/s²

6 0

3 years ago

A train car has a mass of 10,000 kg and is moving at +3.0 m/s. It strikes an identical train car that is at rest. The train cars

VLD [36.1K]

In order to compute the final velocity of the trains, we may apply the principle of conservation of momentum which is:
initial momentum = final momentum
m₁v₁ = m₂v₂

The final mass of the trains will be:
10,000 + 10,000 = 20,000 kg
Substituting the values into the equation:

10,000 * 3 = 20,000 * v
v = 1.5 m/s

The final velocity of the trains will be 1.5 m/s

6 0

3 years ago

Which measurements are equal to 321 decimeters

vlabodo [156]

You are currently converting Distance and Length units from Centimeters to Feet 321 Centimeters (cm) = 10.5315 Feet (ft) This is a hard one but see if this helps if not let me now and i can try again..

7 0

3 years ago