Answer:
Explanation:
Initially no of atoms of A = N₀(A)
Initially no of atoms of B = N₀(B)
5 X N₀(A) = N₀(B)
N = N₀ 
N is no of atoms after time t , λ is decay constant and t is time .
For A
N(A) = N(A)₀ 
For B
N(B) = N(B)₀ 
N(A) = N(B) , for t = 2 h
N(A)₀
= N(B)₀ 
N(A)₀
= 5 x N₀(A) 
= 5 
= 5 
half life = .693 / λ
For A
.77 = .693 / λ₁
λ₁ = .9 h⁻¹
= 5 
Putting t = 2 h , λ₁ = .9 h⁻¹
= 5 
= 30.25
2 x λ₂ = 3.41
λ₂ = 1.7047
Half life of B = .693 / 1.7047
= .4065 hours .
= .41 hours .
Answer:

Explanation:
To find the rotational kinetic energy you first calculate the angular acceleration by using the following formula:

F: force applied
R: radius of the wheel
I: moment of inertia

With this value you calculate the angular velocity:

you calculate how many radians the wheel run in 5.0m


Next, you use the formula for the rotational kinetic energy:

For the transnational kinetic energy you use the following equation:
(net work equals the change in the kinetic energy).
By replacing the you obtain:

Finally, the ratio between translational rotational kinetic energy is:

hence, translational kinetic energy is three times the rotational kinetic energy.
the spring will be compressed by 0.3072 m
Explanation:
acceleration of elevator=3 m/s²
mass of student= 60 Kg
spring constant=2.5 x 10³ N/m
the force on the student is given by F = m ( g +a)
F=60 (9.8+3)
F=768 N
now the formula for spring force is given by
F= k x
768= 2.5 x 10³ (x)
x=0.3072 m
We don't know the change in velocity, so can't answer.