Answer:
1 W = 1 J / sec Definition of watt is 1 joule / sec
So if a bulb uses 75 J / sec it must use
75 J/s * 60 sec / min = 4500 J/min energy used by bulb
If bulb is 15% efficient then the light delivered is
P = 4500 J / min * .15 = 675 J / min
Answer:
A spinning turbine can generate electricity only in the form of an alternating current.
Answer:
P = 251, 3 W
Explanation:
The intensity is defined as the power emitted per unit area
I = P / A
Since sound is distributed in all directions spherical shape, the area of a sphere is
A = 4π r²
let's clear the power and replace
P = I A
P = I (4π r²)
let's calculate
P = 5.00 (4π 2²)
P = 251, 3 W
Answer:
Yes, the calorie can be expressed in SI units
Explanation:
1 calorie (1 cal) is defined as the amount of heat energy that must be supplied to 1 gram of water in order to raise its temperature by 1 degree Celsius (
.
The calorie is not a unit of the International System (SI): the SI unit for the energy is the Joule (J).
However, it is possible to convert energy from calories to Joules, and viceversa. In fact, the conversion factor between the two units is:
1 calorie = 4.184 Joules
So, to convert from calories to Joules we simply multiply by 4.184, while if we want to convert from Joules to calories, we just divide by 4.184.
Answer:
304 meters downstream
Explanation:
The given parameters are;
The speed of the swimmer = 2.00 m/s
The width of the river = 73.0 m
The speed of the river = 8.00 m/s
Therefore;
The direction of the swimmer's resultant velocity = tan⁻¹(8/2) ≈ 75.96° downstream
The distance downstream the swimmer will reach the opposite shore = 4 × 73 = 304 m downstream
The distance downstream the swimmer will reach the opposite shore = 304 m downstream
