A person throws a ball straight up in the air. The ball rises to a maximum height and then falls back down so that the person ca
1 answer:
Answer:
The acceleration is about 9.8 m/s2 (down) when the ball is falling.
Explanation:
The ball at maximum height has velocity zero
t = Time taken
u = Initial velocity
v = Final velocity
s = Displacement
a = Acceleration due to gravity = 9.8 m/s² (positive downward and negative upward)
The accleration 9.8 m/s² will always be acting on the body in opposite direction when the body is going up and in the same direction when the body is going down. The acceleration on the body will never be zero
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Answer:
here as we increase the distance the intensity will decrease and hence the amplitude of the electric field will decrease and vice-versa
Explanation:
As wee know that the amplitude of the wave will decide the energy of the wave
Here we know that energy density of electromagnetic wave is given as
now we have
so here we can say that intensity of the wave at the given distance from the source is given by formula
so here as we increase the distance the intensity will decrease and hence the amplitude of the electric field will decrease and vice-versa.
Answer:
A mass of 10 kilograms lifted 10 meters in 5 seconds.
Explanation:
Power can be defined as the energy required to do work per unit time.
Mathematically, it is given by the formula;
But Energy = mgh
Substituting into the equation, we have
Given the following data;
Mass = 10kg
Height = 10m
Time = 5 seconds
We know that acceleration due to gravity is equal to 9.8 m/s²
Hence, a mass of 10 kilograms lifted 10 meters in 5 seconds would produce the most power.
Work needed: 720 J
Explanation:
The work needed to stretch a spring is equal to the elastic potential energy stored in the spring when it is stretched, which is given by
where
k is the spring constant
x is the stretching of the spring from the equilibrium position
In this problem, we have
E = 90 J (work done to stretch the spring)
x = 0.2 m (stretching)
Therefore, the spring constant is
Now we can find what is the work done to stretch the spring by an additional 0.4 m, that means to a total displacement of
x = 0.2 + 0.4 = 0.6 m
Substituting,
Therefore, the additional work needed is
Learn more about work:
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