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3 years ago

Please help!!!!! (and explain if you can) thank you so SO much!!! will give brainliest

Physics

2 answers:

Anna [14]3 years ago

4 0

Answer:

negative because it they oppose they are going to make the ball float (like when tried to put the same sides of magnets to touch)

Explanation:

Marina CMI [18]3 years ago

4 0

I believe it’s negative :)

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A train travels 600 km in one hour. What is the trains velocity in meters/second

eimsori [14]

v= s/t

600 ÷ 60

10 m/s

4 0

4 years ago

Read 2 more answers

Light-rail passenger trains that provide transportation within and between cities are capable of modest accelerations. The magni

Mkey [24]

During the first phase of acceleration we have:
v o = 4 m/s; t = 8 s; v = 13 m/s, a = ?
v = v o + a * t
13 m/s = 4 m / s + a * 8 s
a * 8 s = 9 m/s
a = 9 m/s : 8 s
a = 1.125 m/s²
The final speed:
v = ?; v o = 13 m/s; a = 1.125 m/s² ; t = 16 s
v = v o + a * t
v = 13 m/s + 1.125 m/s² * 16 s
v = 13 m/s + 18 m/s = 31 m/s

3 0

3 years ago

g calculate the effectiveness radiation dosage in sieverts for a 79 kg person who is exposed 6.8x10^9

Elza [17]

Answer:

The answer is " $\bold{dosage = 0.031 rem}$ "

Explanation:

please find the complete question in the attached file.

Given value:

$m = 79\ kg \\\\n = 3.4 \times 10^9 \\\\E = 5.5 \times 10^{-13} \\\\ RBE = 15$

$\to E = n E\\$

$= 3.4 \times 10^9 \times 5.5 \times 10^{-13} \\\\ = 1.87 \times 10^{-3}$

$\to E(absorbed) = 1.87 \times 10^{-3} \times 0.87 = 1.63 \times 10^{-3}$

calculating the radiation absorbed per kg:

$= \frac{1.63 \times 10^{-3}}{79} \\\\ = 2.06 \times 10^{-5} \\\\ = 0.00206 \ rad$

$\to Dosage = 0.00206 \times 15 \\$

$= 0.031 \ \ rem$

4 0

3 years ago

At the beginning of a unit on forces, Ms. Alton is leading a class discussion asking her students

VMariaS [17]

Answer:

(iv), (v), (vi) would be incorrect.

Explanation:

(iv) Force isn't transferred from one colliding object to another, but momentum can be.

(v) An object doesn't stop immediately a force stops acting on it. Think of a thrown ball.

(vi) For an object not to move, it means that the net force on the object is zero, and not necessarily that there are no forces acting on the object. For example, an object could be pushed on one side, and be pushed on the other side with an equal force in the opposite direction. The forces would cancel each other and the net force would be zero.

The rest should be correct.

6 0

3 years ago

Suppose a 65 kg person stands at the edge of a 6.5 m diameter merry-go-round turntable that is mounted on frictionless bearings

ozzi

Answer:

$0.3165\ \text{rad/s}$

Explanation:

m = Mass of person = 65 kg

d = Diameter of round table = 6.5 m

r = Radius = $\dfrac{d}{2}=3.25\ \text{m}$

v = Velocity of person running = 3.8 m/s

$I_t$ = Moment of inertia of turntable = $1850\ \text{kg m}^2$

Moment of inertia of the system is

$I=I_t+mr^2\\\Rightarrow I=1850+65\times 3.25^2\\\Rightarrow I=2536.5625\ \text{kg m}^2$

As the angular momentum of the system is conserved we have

$L_i=L_f\\\Rightarrow mvr=I\omega_f\\\Rightarrow \omega_f=\dfrac{mvr}{I}\\\Rightarrow \omega_f=\dfrac{65\times 3.8\times 3.25}{2536.5625}\\\Rightarrow \omega_f=0.3165\ \text{rad/s}$

The angular velocity of the turntable is $0.3165\ \text{rad/s}$ .

3 0

3 years ago

Please help!!!!! (and explain if you can) thank you so SO much!!! *will give brainliest*

Please help!!!!! (and explain if you can) thank you so SO much!!! will give brainliest