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3 years ago

10

True or false Heat, visible light, radio waves, x rays are waves that do not need a medium to travel through. They are called me

dium rare.

1 answer:

kondor19780726 [428]3 years ago

4 0

Answer:

true

Explanation:

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A 5.50-kg object is hung from the bottom end of a vertical spring fastened to an overhead beam. The object is set into vertical

iris [78.8K]

Answer:

17.71N/m

Explanation:

The period of the spring is expressed according to the expression;

$T = 2 \pi \sqrt{\frac{m}{k} } \\$

m is the mass of the object

k is the force constant

Given

m = 5.50kg

T = 3.50s

Substitute into the formula;

$T = 2 \pi \sqrt{\frac{m}{k} } \\3.5 = 2 (3.14) \sqrt{\frac{5.5}{k} } \\3.5 = 6.28 \sqrt{\frac{5.5}{k} } \\\frac{3.5}{6.28} = \sqrt{\frac{5.5}{k} } \\0.557 = \sqrt{\frac{5.5}{k} } \\square \ both \ sides\\0.557^2 = (\sqrt{\frac{5.5}{k} })^2 \\0.3106 = \frac{5,5}{k}\\k = \frac{5.5}{0.3106}\\k = 17.71N/m$

Hence the force constant of the spring is 17.71N/m

4 0

3 years ago

4. A high school athlete runs 400 m in 52.20 sec. What is his speed in mph?<br> 14100<br> 1110

Serggg [28]

Answer:

28,800m/p second

Explanation:

Calculate the distance per second so, 400m/50 s= 8m/p second now knowing the speed/hour and knowing an hour has 3,600 seconds,multiply it by 8 then you will get 28,800m/p second, or 28.8km/h

3 0

3 years ago

You take the same 3 kg metal block and slide it along the floor, where the coefficient of friction is only 0.4. You release the

spin [16.1K]

Answer:

1.52905 seconds

4.58715 m

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

$\mu$ = Coefficient of friction = 0.4

g = Acceleration due to gravity = 9.81 m/s²

a = Acceleration = $\mu g$

Equation of motion

$v=u+at\\\Rightarrow t=\frac{v-u}{\mu g}\\\Rightarrow t=\frac{0-6}{-0.4\times 9.81}\\\Rightarrow t=1.52905\ s$

It will take 1.52905 seconds for the block to slow down

$v^2-u^2=2as\\\Rightarrow s=\frac{v^2-u^2}{2\mu g}\\\Rightarrow s=\frac{0^2-6^2}{2\times 0.4\times -9.81}\\\Rightarrow s=4.58715\ m$

The block will travel 4.58715 m before it stops

7 0

3 years ago

A pitcher throws a baseball with a mass of 143 g horizontally at a speed of 38.8 m/s (87 mi/h). The hitter's bat is in contact w

SIZIF [17.4K]

Answer:

F = −10093.41 N

Explanation:

Given that,

Mass of a baseball, m = 143 g = 0.143 kg

Initial speed of the baseball, u = +38.8 m/s

The hitter's bat is in contact with the ball for 1.20 ms and then travels straight back to the pitcher's mound at a speed of 45.9 m/s, v = -45.9 m/s

We need to find the average force exerted on the ball by the bat. So, Force is given by :

$F=ma$

a is acceleration

$F=\dfrac{m(v-u)}{t}\\\\F=\dfrac{0.143\times (-45.9-(38.8))}{1.2\times 10^{-3}}\\\\F=-10093.41\ N$

So, the average force exerted on the ball by the bat has a magnitude of 10093.41 N.

8 0

4 years ago

Anything that causes change must have energy?

Makovka662 [10]

This is a true fact.
Example: An object sitting still in place has energy called potential energy so if an object moving, kinetic energy, and pushes the other object not moving, then the potential energy object will now have kinetic energy; Change.

So, that IS a true fact.

I hope this helped!

8 0

3 years ago