Answer:
Explanation:
The cabinet does not move: this means that the net force acting on it is zero.
Along the horizontal direction, we have two forces:
- The push exerted by Bob, F = 200 N, forward
- The frictional force, 
, which acts in the opposite direction (backward)
Since the net force must be zero, we have:
So solving the equation we can find the magnitude of the friction force:
The skier's speed at time <em>t</em> is
<em>v</em> = (23 m/s²) <em>t</em>
To reach a speed of 9.3 m/s, the skier would need
9.3 m/s = (23 m/s²) <em>t</em>
<em>t</em> = (9.3 m/s) / (23 m/s²)
<em>t</em> ≈ 0.404 s
Missing part in the text of the problem:
"<span>Water is exposed to infrared radiation of wavelength 3.0×10^−6 m"</span>
First we can calculate the amount of energy needed to raise the temperature of the water, which is given by
where
m=1.8 g is the mass of the water
is the specific heat capacity of the water
is the increase in temperature.
Substituting the data, we find
We know that each photon carries an energy of
where h is the Planck constant and f the frequency of the photon. Using the wavelength, we can find the photon frequency:
So, the energy of a single photon of this frequency is
and the number of photons needed is the total energy needed divided by the energy of a single photon:
Answer:
Explanation:
Newton's first law states that, if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force. This postulate is known as the law of inertia.
hope this helps :))
Gravity? Im almost sure thats it
