Answer:
62.64 RPM.
Explanation:
Given that
m= 4.6 g
r= 19 cm
μs = 0.820
μk = 0.440.
The angular speed of the turntable = ω rad/s
Condition just before the slipping starts
The maximum value of the static friction force =Centripetal force


Therefore the speed in RPM will be 62.64 RPM.
Answer:

ΔK = 2.45 J
Explanation:
a) Using the law of the conservation of the linear momentum:

Where:


Now:

Where
is the mass of the car,
is the initial velocity of the car,
is the mass of train,
is the final velocity of the car and
is the final velocity of the train.
Replacing data:

Solving for
:

Changed to cm/s, we get:

b) The kinetic energy K is calculated as:
K = 
where M is the mass and V is the velocity.
So, the initial K is:



And the final K is:




Finally, the change in the total kinetic energy is:
ΔK = Kf - Ki = 22.06 - 19.61 = 2.45 J
Answer:
ثر أنواع التربة خصوبة التربحمراء .
ج- السوداء
Explanation:
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