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3 years ago

Why do helium balloons float? Talk about density of atoms and compare to elements in the air.

1 answer:

7 0

The helium balloon displaces an amount of air. As long as the weight of the helium balloon fabric is lighter than the air it displaces, the balloon will float in the air. It turns out helium is a lot lighter than air.

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A student holds a bike wheel and starts it spinning with an initial angular speed of 9.0 rotations per second. The wheel is subj

KATRIN_1 [288]

Answer:

$\Delta t = 8 s$

Explanation:

As we know that the angular acceleration of the wheel due to friction is constant

so we can use kinematics

$\theta = \omega_i t + \frac{1}{2}\alpha t^2$

so we have

$(65 \times 2\pi) = (2\pi \times 9)(10) + \frac{1}{2}(\alpha)(10^2)$

$130\pi = 180\pi + 50 \alpha$

$\alpha = -\pi rad/s^2$

now time required to completely stop the wheel is given as

$\omega_f = \omega_i + \alpha t$

$0 = (2\pi \times 9) + (-\pi) t$

$t = 18 s$

now time required to stop the wheel is given as

$\Delta t = 18 - 10$

$\Delta t = 8 s$

6 0

3 years ago

A cart of mass 0.8 kg on a horizontal frictionless track has a tension of 4 N applied to on side of the cart. Calculate the acce

sweet [91]

Answer:

Option (c).

Explanation:

Given that,

Mass of a cart, m = 0.8 kg

Tension in the car, F = 4 N

Net force, F = ma

a is acceleration of the cart.

So,

$a=\dfrac{F}{m}\\\\a=\dfrac{4\ N}{0.8\ kg}\\\\a=5\ m/s^2$

So, the acceleration of the cart is $5\ m/s^2$ .

7 0

3 years ago

The mass of a large car is 1000 kg. How much force would be required to accelerate the car at a rate of 3msec2

pogonyaev

Answer:

3000 N

Explanation:

We have,

• Mass, m = 1000 kg

• Acceleration, a = 3 m/s²

We have to find force required, F.

$\longrightarrow$ F = ma

$\longrightarrow$ F = 1000 × 3 N

$\longrightarrow$ F = 3000 N (Answer)

8 0

2 years ago

The design process for technology often requires many failed solutions before developing a successful solution. What is the prim

Whitepunk [10]

A. The primary benefit of this process is each failed design provides more information for the next design.

<h3>What is design process for technology?</h3>

Design process for technology are the steps used to obtain a desired technological results.

Technological design process include:

identify a problem,
research the problem,
generate possible solutions,
select the best solution, create a model,
test the model,
refine and retest the model as needed,
communicate the final solution.

During technological design process, a failed result can provide a greater insights for the next step necessary for the end goal.

Thus, the primary benefit of this process is each failed design provides more information for the next design.

Learn more about technological design process here: brainly.com/question/20162876

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3 0

2 years ago

1. A 0.250 kg baseball sits on the ledge of a window in Treadwell hall. If the ball has 18.5

Lunna [17]

Answer:

h = 7.54 m

t = 1.24 s

Explanation:

1.Let g = 9.81 m/s2 is the gravitational acceleration. Since the formula for potential energy is:

$E_p = mgh$

where m = 0.25 is the ball mass and h is the height. We can solve for h

$h = \frac{E_p}{mg} = \frac{18.5}{0.25*9.81} = 7.54m$

2. The time it take for the ball to reach a distance of 7.54m with a gravitational acceleration of 9.81m/s2:

$h = \frac{gt^2}{2}$

$t^2 = \frac{2h}{g} = \frac{2*7.54}{9.81} = 1.54$

$t = \sqrt{1.54} = 1.24 s$

4 0

3 years ago