Answer: 8.81 J
Explanation: The scalar or dot product of 2 vector equals the product of the magnitude of both vectors and the cosine value of the angle between them
Magnitude of vector f (force) as given in the question = 12.5N
Magnitude of length = 0.75m
Angle between vectors = 25°
F. Δr = 12.5 * 0.75 * cos 25
F. Δr = 12.5 * 0.75 * 0.9063
F. Δr = 8.81 J
Answer:
The correct solution is:
(a) 
(b) 
(c) 
(d) 
Explanation:
The given values are:
Effective duration of the flash,
ζ = 0.25 s
Average power,


Average voltage,

Now,
(a)
⇒ 
On substituting the values, we get
⇒ 
⇒ 
(b)
⇒ 
then,
⇒ 
On substituting the values, we get
⇒ 
⇒ 
(c)
⇒ 
⇒ 
⇒ 
(d)
As we know,
⇒ 
⇒ 
⇒ 
⇒ 
243000, take the 4,860 and times it by 50
Answer:
B = 62.9 N
Explanation:
This is an exercise on Archimedes' principle, where the thrust force equals the weight of the liquid
B = ρ g V
write the equilibrium equation
T + B -W = 0
B = W- T (1)
use the density to write the weight
ρ = m / V
m = ρ V
W = ρ g V
substitute in 1
B = m g -T
B =
g V - T
To finish the calculation, the density of the material must be known, suppose it is steel \rho_{body} = 7850 kg / m³
calculate
B = 7850 9.8 1.20 10⁻³ - 29.4
B = 92.3 - 29.4
B = 62.9 N