Всяко действие има равно по големина и противоположно по посока противодействие.
Answer:
No
Explanation:
In the photoelectric effect,
The number of the electrons which are being emitted is directly proportional to the intensity of the light and is independent on the frequency of the incident radiation of the light which has the frequency greater than the threshold frequency.
Thus, on increasing the frequency of the light which is being shinned on the metal , there is no change in the electrons which are being emitted.
In the first law, an object will not change its motion unless a force acts on it. So I think the answer is A. Only objects that are moving.
Momentum is a vector, although we don't hammer on that. In order to completely describe a momentum, you need a magnitude AND a direction ... just like force and velocity.
So choice #2 is the magnitude of a momentum, without its direction.
<em>Choice #3</em> is the full package, with both the magnitude and the direction.
Choice #1 has units of energy, and choice #4 has units of acceleration, so neither of those can be it.
1.) The force of gravity is what we call weight, we define it as:
w=mg
w=5,7kg*9,8m/s²
w=55,86kg (b)
2.) We know that:
power=W/t
power=50J/20s
power=2,5Watts (a)
3.) The work done is equal to the potential energy, so:
Epg=mgh
Epg=63kg*9,8m/s²*7m
Epg=4321J
Now we get the power:
power=W/t
power=4321J/5s
power=864Watts
Now:
1HP=746Watts
=1,16HP (b)
4.) We know that:
F=ma
350N=m*10m/s²
m=350N/10m/s²
m=35kg (b)
5.) d.) Aceleration is tha rate of change in velocity, either positive (increasing) or negative (decreasing)
