Answer:
Around 3.57m/s
Explanation:
p=mv
Let's denote the momentum, mass, and velocity of the car with the subscript 1, and for the truck use 2. After the collision, the combined momentum can be denoted with the subscript 3.

Hope this helps!
Explanation:
Power output of the bulb:
0.021 × 60 W = 1.26 W
Energy produced by the bulb in 1 second:
E = Pt
E = (1.26 W) (1 s)
E = 1.26 J
Round as needed.
I just did this last semester... I know this is wave height!!
Answer:
Explanation:
The energy of a photon is given by the equation
, where h is the <em>Planck constant</em> and f the frequency of the photon. Thus, N photons of frequency f will give an energy of
.
We also know that frequency and wavelength are related by
, so we have
, where c is the <em>speed of light</em>.
We will want the number of photons, so we can write

We need to know then how much energy do we have to calculate N. The equation of power is
, so for the power we have and considering 1 second we can calculate the total energy, and then only consider the 4% of it which will produce light, or better said, the N photons, which means it will be
.
Putting this paragraph in equations:
.
And then we can substitute everything in our equation for number of photons, in S.I. and getting the values of constants from tables:
