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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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Holly puts a box into the trunk of her car. Later, she drives around an unbanked curve that has a radius of 48 m. The speed of t

LiRa [457]

Answer:

The minimum coefficient of friction is 0.544

Solution:

As per the question:

Radius of the curve, R = 48 m

Speed of the car, v = 16 m/s

To calculate the minimum coefficient of static friction:

The centrifugal force on the box is in the outward direction and is given by:

$F_{c} = \frac{mv^{2}}{R}$

$f_{s} = \mu_{s}mg$

where

$\mu_{s}$ = coefficient of static friction

The net force on the box is zero, since, the box is stationary and is given by:

$F_{net} = f_{s} - F_{c}$

$0 = f_{s} - F_{c}$

$\mu_{s}mg = \frac{mv^{2}}{R}$

$\mu_{s} = \frac{v^{2}}{gR}$

$\mu_{s} = \frac{16^{2}}{9.8\times 48} = 0.544$

3 0

3 years ago

William wanted to create a report on a geographical location with the greatest species diversity. Which ecosystem can consider f

FrozenT [24]

Answer:

The ecosystem that he should consider is the tropical rain forest ecosystem.

Explanation:

In that area, there are uncountable amounts of various plants and animals that have not all yet been discovered and who all live together to build the biome. This biome is indeed the most diverse one even at this point without the knowledge of all possible life forms.

8 0

3 years ago

A thin uniform rod of mass M and length L is bent at its center so that the two segments are now perpendicular to each other. Fi

Tatiana [17]

Answer:

(a) I_A=1/12ML²

(b) I_B=1/3ML²

Explanation:

We know that the moment of inertia of a rod of mass M and lenght L about its center is 1/12ML².

(a) If the rod is bent exactly at its center, the distance from every point of the rod to the axis doesn't change. Since the moment of inertia depends on the distance of every mass to this axis, the moment of inertia remains the same. In other words, I_A=1/12ML².

(b) The two ends and the point where the two segments meet form an isorrectangle triangle. So the distance between the ends d can be calculated using the Pythagorean Theorem:

$d=\sqrt{(\frac{1}{2}L) ^{2}+(\frac{1}{2}L) ^{2} } =\sqrt{\frac{1}{2}L^{2} } =\frac{1}{\sqrt{2} } L=\frac{\sqrt{2} }{2} L$

Next, the point where the two segments meet, the midpoint of the line connecting the two ends of the rod, and an end of the rod form another rectangle triangle, so we can calculate the distance between the two axis x using Pythagorean Theorem again:

$x=\sqrt{(\frac{1}{2}L)^{2}-(\frac{\sqrt{2}}{4}L) ^{2} } =\sqrt{\frac{1}{8} L^{2} } =\frac{1}{2\sqrt{2}} L=\frac{\sqrt{2}}{4} L$

Finally, using the Parallel Axis Theorem, we calculate I_B:

$I_B=I_A+Mx^{2} \\\\I_B=\frac{1}{12} ML^{2} +\frac{1}{4} ML^{2} =\frac{1}{3} ML^{2}$

5 0

2 years ago

A ball is dropped from a height of 180m- Calculate the velocity of the ball when it strikes the ground

gayaneshka [121]

Answer:

6s , 60mls

Explanation:

hope this helps love

6 0

3 years ago

Read 2 more answers

Please hurry this is urgent right answers only!!!!!

dem82 [27]

Explanation:

if two individual forces are of equal magnitude and opposite direction, then the force is said to be balanced. when there is an individual force that is not being balanced by a force of equal magnitude and in the opposite direction.

6 0

3 years ago