Answer:
240 Ω
Explanation:
Resistance: This can be defined as the opposition to the flow of current in an electric field. The S.I unit of resistance is ohms (Ω).
The expression for resistance power and voltage is give as,
P = V²/R.......................... Equation 1
Where P = Power, V = Voltage, R = Resistance
Making R the subject of the equation,
R = V²/P.................... Equation 2
Given: V = 120 V, P = 60 W.
Substitute into equation 2
R = 120²/60
R = 240 Ω
Hence the resistance of the bulb = 240 Ω
Answer:
- 278.34 kg m/s^2
Explanation:
The rate of the change of momentum is the same as the force.
The force that an object feels when moviming in a circular motion is given by:
F = -mrω^2
Where ω is the angular speed and r is the radius of the circumference
Aditionally, the tangential velocity of the body is given as:
v = rω
The question tells us that
v = 25 m/s
r = 7m
mv = 78 kg m/s
Therefore:
m = (78 kg m/s) / (25 m/s) = 3.12 kg
ω = (25 m/s) / (7 m) = 3.57 (1/s)
Now, we can calculate the force or rate of change of momentum:
F = - (3.12 kg) (7 m)(3.57 (1/s))^2
F = - 278.34 kg m/s^2
m = mass held by mr. Z above his head = 200 kg
g = acceleration due to gravity = 9.8 m/s²
F = force applied by mr. Z to hold the mass
Using equilibrium of force , force equation is given as
F = mg
F = (200) (9.8)
F = 1960 N
Since the mass is not moved,
d = displacement of the mass = 0 m
we know that , work done is given as
W = F d
inserting the values
W = (1960) (0)
W = 0 J
