First compute the resultant force F:



Then use Newton's second law to determine the acceleration vector
for the particle:



Let
and
denote the particle's position and velocity vectors, respectively.
(a) Use the fundamental theorem of calculus. The particle starts at rest, so
. Then the particle's velocity vector at <em>t</em> = 10.4 s is



If you don't know calculus, then just use the formula,

So, for instance, the velocity vector at <em>t</em> = 10.4 s has <em>x</em>-component

(b) Compute the angle
for
:

so that the particle is moving at an angle of about 313º counterclockwise from the positive <em>x</em> axis.
(c) We can find the velocity at any time <em>t</em> by generalizing the integral in part (a):


Then using the fundamental theorem of calculus again, we have

where
is the particle's initial position. So we get



So over the first 10.4 s, the particle is displaced by the vector

or a net distance of about 395 m away from its starting position, in the same direction as found in part (b).
(d) See part (c).
D= 9.7^3/(69)(4.2)^2
d=912.673/289.8^2
d=912.673/83984.04
d=0.01086721953362...
I hope this helped!
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 .
Mass of the dart = 0.01 kg
Speed at which the dart is thrown = 20 m/s
Kinetic Energy = (1/2) * mass * speed * speed
= (1/2) * (0.01) * (20) * (20) Joules
= (400 *0.01)/2 Joules
= 4/2 Joules
= 2 Joules
So the kinetic energy of the dart is 2 Joules. I hope this is the correct answer and it has helped you.
Gravity is pulling the book towards the center of the earth, and the rebounding effect of the table cancelling out gravity allowing for the book to sit at rest.