Explanation:
Power is defined as the work done per unit time or
For a top player, a tennis ball may leave the racket on the serve with a speed of 55 m/s (about 120 mi/h). If the ball has a mas
1 answer:
Answer:
Yes is large enough
Explanation:
We need to apply the second Newton's Law to find the solution.
We know that,
And we know as well that
Replacing the aceleration value in the equation force we have,
Substituting our values we have,
The weight of the person is then,
<em>We can conclude that force on the ball is large to lift the ball</em>
You might be interested in
1) Destructive interference
The condition for constructive interference to occur is:
(1)
where
is the path difference, with
is the distance of the point from the first source
is the distance of the point from the second source
m is an integer number
is the wavelength
In this problem, we have
So let's use eq.(1) to see if the resulting m is an integer
It is not an integer so constructive interference does not occur.
Let's now analyze the condition for destructive interference:
(2)
If we apply the same procedure to eq.(2), we find
which is an integer: so, this point is a point of destructive interference.
2) Constructive interference
In this case we have
So the path difference is
Using the condition for constructive interference:
Which is an integer, so this is a point of constructive interference.
3) Destructive interference
In this case we have
So the path difference is
Using the condition for constructive interference:
This is not an integer, so this is not a point of constructive interference.
So let's use now the condition for destructive interference:
which is an integer: so, this point is a point of destructive interference.
Answer:
It must be 4 times high.
Explanation:
- Assuming that the car can be treated as a point mass, and that the ramp is frictionless, the total mechanical energy must be conserved.
- This means, that at any time, the following must be true:
- ΔK (change in kinetic energy) = ΔU (change in gravitational potential energy)
⇒
- Let's call v₁, to the final speed of the car, and h₁ to the height of the ramp.
So, at the bottom of the ramp, all the gravitational potential energy
must be equal to the kinetic energy of the car (Defining the bottom of
the ramp as our zero reference for the gravitational potential energy):
(1)
- Now, let's do v₂ = 2* v₁
- Replacing in (1) we get:
(2)
- Dividing (2) by (1), and rearranging terms, we get:
- h₂ = 4* h₁
Answer:
The kinetic energy of the phone would increase. The gravitational potential energy of the phone would decrease.
Explanation:
The kinetic energy of an object is proportional to the square of the speed of that object. If air resistance is negligible, the phone would accelerate under gravitational pull and speed up. Hence, the kinetic energy of the phone would increase.
The gravitational field near the surface of the earth is approximately constant. Hence, the gravitational potential energy of the phone would be proportional to its height. As the phone approaches the ground, the height of the phone becomes lower and the gravitational potential energy of the phone would decrease.