Answer:
See explanation
Explanation:
The degradation of the drug is a first order process;
Hence;
ln[A] = ln[A]o - kt
Where;
ln[A] = final concentration of the drug
ln[A]o= initial concentration of the drug = 5 gm/100
k= degradation constant = 0.05 day-1
t= time taken
When [A] =[ A]o - 0.5[A]o = 0.5[A]o
ln2.5 = ln5 - 0.05t
ln2.5- ln5 = - 0.05t
t= ln2.5- ln5/-0.05
t= 0.9162 - 1.6094/-0.05
t= 14 days
b) when [A] = [A]o - 0.9[A]o = 0.1[A]o
ln0.5 = ln5 -0.05t
t= ln0.5 - ln5/0.05
t= -0.693 - 1.6094/-0.05
t= 46 days
Answer:
4500 N
Explanation:
When a body is moving in a circular motion it will feel an acceleration directed towards the center of the circle, this acceleration is:
a = v^2/r
where v is the velocity of the body and r is the radius of the circumference:
Therefore, a body with mass m, will feel a force f:
f = m v^2/r
Therefore we need another force to keep the body(car) from sliding, this will be given by friction, remember that friction force is given a the normal times a constant of friction mu, that is:
fs = μN = μmg
The car will not slide if f = fs, i.e.
fs = μmg = m v^2/r
That is, the magnitude of the friction force must be (at least) equal to the force due to the centripetal acceleration
fs = (1000 kg) * (30m/s)^2 / (200 m) = 4500 N
Answer:
P = 17.28*10⁶ N
Explanation:
Given
L = 250 mm = 0.25 m
a = 0.54 m
b = 0.40 m
E = 95 GPa = 95*10⁹ Pa
σmax = 80 MPa = 80*10⁶ Pa
ΔL = 0.12%*L = 0.0012*0.25 m = 3*10⁻⁴ m
We get A as follows:
A = a*b = (0.54 m)*(0.40 m) = 0.216 m²
then, we apply the formula
ΔL = P*L/(A*E) ⇒ P = ΔL*A*E/L
⇒ P = (3*10⁻⁴ m)*(0.216 m²)*(95*10⁹ Pa)/(0.25 m)
⇒ P = 24624000 N = 24.624*10⁶ N
Now we can use the equation
σ = P/A
⇒ σ = (24624000 N)/(0.216 m²) = 114000000 Pa = 114 MPa > 80 MPa
So σ > σmax we use σmax
⇒ P = σmax*A = (80*10⁶ Pa)*(0.216 m²) = 17280000 N = 17.28*10⁶ N
