<u>Answer:</u> The velocity of released alpha particle is 
<u>Explanation:</u>
According to law of conservation of momentum, momentum can neither be created nor be destroyed until and unless, an external force is applied.
For a system:

where,
= Initial mass and velocity
= Final mass and velocity
We are given:

Putting values in above equation, we get:

Hence, the velocity of released alpha particle is 
Answer:
(4)
more protons than electrons
Explanation:
Total positive change on the object is given as

now by the law of quantization of charge we know that the charge on any body is always in form of integral multiple of charge of an electron.
So we will have

here we know that


Now we know that the object is positively charged so here electrons must be less in numbers than protons
so correct answer will be
(4)
more protons than electrons
Answer:
1989.6Kg
Explanation:
The computation of the mass of the other body is given below:
As we know that
F = G × m1 × m2 ÷ r²
Here the G would have the constant value i.e. 6.67 × 10^-11Nm² / kg².
Now
6.5 × 10^-7N = 6.67 × 10^-11Nm² / kg² × 60Kg × m2 / (3.5m) ²
m2 = (F × r²) / (G × m1)
m2 = (6.5 × 10^-7N × (3.5m) ²) ÷ (6.67 × 10^-11Nm² / kg² × 60Kg)
= 1989.6Kg
The question is incomplete. The complete question is :
In your job as a mechanical engineer you are designing a flywheel and clutch-plate system. Disk A is made of a lighter material than disk B, and the moment of inertia of disk A about the shaft is one-third that of disk B. The moment of inertia of the shaft is negligible. With the clutch disconnected, A is brought up to an angular speed ?0; B is initially at rest. The accelerating torque is then removed from A, and A is coupled to B. (Ignore bearing friction.) The design specifications allow for a maximum of 2300 J of thermal energy to be developed when the connection is made. What can be the maximum value of the original kinetic energy of disk A so as not to exceed the maximum allowed value of the thermal energy?
Solution :
Let M.I. of disk A = 
So, M.I. of disk B = 
Angular velocity of A = 
So the kinetic energy of the disk A = 
After coupling, the angular velocity of both the disks will be equal to ω.
Angular momentum will be conserved.
So,



Now,






Therefore, the maximum initial K.E. = 3066.67 J
Because heat keeps us warm and water hydrates the planet i guess?????
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