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3 years ago

When water in a lake freezes, the ice that forms floats on top of any water that is still liquid. Why does the ice float?

Physics

1 answer:

ddd [48]3 years ago

5 0

Answer:

it floats because the lake is cold at that moment so when part of the lake freezes it still remains solid and floats because of the lake and the surrounding of the lake is still cold

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Will name brainliest please pleas answer

Greeley [361]

3 is the answer teeeeeeeeeheeeeeeeee

6 0

3 years ago

A cyclist accelerates from a velocity of 10 miles/hour east until reaching a velocity of 20 miles/hour east in 5 seconds. What w

Sliva [168]

Answer:

$a = 0.894\ m/s^2$

Explanation:

<u>Motion with Constant Acceleration</u>

A body moves with constant acceleration when the speed changes uniformly in time. The equation used to find the final speed vf is

$v_f=v_o+at$

Where vo is the initial speed, a is the acceleration, and t is the time.

The cyclist has an initial speed of vo=10 miles/hour and ends up at vf=20 miles/hour in t=5 seconds.

Both speeds are given in miles/hour and we must convert it to m/s:

1 mile/hour = 0.44704 m/s

10 mile/hour = 4.47 m/s

20 mile/hour = 8.94 m/s

The acceleration is calculated by solving for a:

$\displaystyle a=\frac{v_f-v_o}{t}$

$\displaystyle a=\frac{8.94-4.47}{5}$

$a = 0.894\ m/s^2$

3 0

3 years ago

To practice Problem-Solving Strategy 30.1: Inductors in Circuits. A circuit has a 1 V battery connected in series with a switch.

ki77a [65]

Answer:

0.0133A

Explanation:

Since we have two sections, for the Inductor region there would be a current $i_1$ . In the case of resistance 2, it will cross a current $i_2$

Defined this we proceed to obtain our equations,

For $i_1$ ,

$\frac{di_1}{dt}+i_1R_1 = V$

$I_1 = \frac{V}{R_1} (1-e^{-\frac{R_1t}{L}})$

For $i_2$ ,

$I_2R_2 =V$

$I_2 = \frac{V}{R_2}$

The current in the entire battery is equivalent to,

$i_t = I_1+I_2$

$i_t = \frac{V}{R_2}+\frac{V}{R_1} (1-e^{-\frac{R_1t}{L}})$

Our values are,

$V=1V$

$R_1 = 95\Omega$

$L= 1.5*10^{-2}H$

$R_2 =360\Omega$

Replacing in the current for t= 0.4m/s

$i=\frac{1}{360}+\frac{1}{95}(1-e^{-\frac{95*0.4}{1.5*10^{-2}}})$

$i= 0.0133A$

$i_1 = 0.01052A$

3 0

3 years ago

Define and Explain the Sovereignty

GarryVolchara [31]

Sovereignty is a political concept that refers to dominant power or supreme authority.

Explanation:

Sovereignty is an attribute of states that is both an idea and a reality of state power. It is one of the means, an important one, by which the government of a state seeks to ensure the best it possibly can for its people. As such, it also changes over time.

6 0

3 years ago

A 45.0 kg skier testing a new competitive ski wax drops off a ledge, goes into a crouch and goes straight down a slope of 10.0◦

Neko [114]

Answer:

v = 21.03 m/s

Explanation:

given,

mass of skier = 45 kg

the slope of the snow = 10.0◦

coefficient of friction = 0.114

distance traveled = 300 m

speed = ?

Acceleration = g sin θ - µ g Cos θ

= 9.8 × Sin (10°) - 0.10 × 9.8 × Cos(10°)

= 0.737 m/s²

using equation of motion

v² = u² + 2 a s

v² = 0 + 2 × 0.737 × 300

v = 21.03 m/s

Speed of skier's after travelling 300 m speed is equal to 21.03 m/s

6 0

3 years ago