Answer:
Answer D : about 1067 meters
Explanation:
There are two steps to this problem:
1) First find the time it takes the plane to stop using the equation for the acceleration:
Where Vf is the final velocity of the plane (in our case: zero )
Vi is the initial velocity of the plane (in our case: 80 m/s)
is the acceleration (in our case -3 m/s^2 - notice negative value because the velocity is decreasing)
with units corresponding to seconds given the quantities involved in the calculation.
2) Second knowing the time it took the plane to stop, now use that time in the equation for the distance traveled under accelerated motion:
Where the answer results in units of meters given the quantities used in the calculation.
We round this to 1067 meters
1) Focal length
We can find the focal length of the mirror by using the mirror equation:
(1)
where
f is the focal length
is the distance of the object from the mirror
is the distance of the image from the mirror
In this case,
, while
(the distance of the image should be taken as negative, because the image is to the right (behind) of the mirror, so it is virtual). If we use these data inside (1), we find the focal length of the mirror:
from which we find
2) The mirror is convex: in fact, for the sign convention, a concave mirror has positive focal length while a convex mirror has negative focal length. In this case, the focal length is negative, so the mirror is convex.
3) The image is virtual, because it is behind the mirror and in fact we have taken its distance from the mirror as negative.
4) The radius of curvature of a mirror is twice its focal length, so for the mirror in our problem the radius of curvature is:
The frequency of the
scattered photon decreases or it will be lower compare to the frequency of
incident photon. An x-ray photon scatters in one direction after a collision
and some energy is transferred to the electron as it recoils in another
direction resulting to have less energy in the scattered photon. In addition, the
frequencies will also depend on the differences of the angle at which the
scattered photon leaves the collision and this incident is called Compton Effect.
Answer:
Explanation:
In order to solve this problem, we can do an analysis of the energies involved in the system. Basically the addition of the initial potential energy of the spring and the kinetic energy of the mass should be the same as the addition of the final potential energy of the spring and the kinetic energy of the block. So we get the following equation:
In this case, since the block is moving from rest, the initial kinetic energy is zero. When the block loses contact with the spring, the final potential energy of the spring will be zero, so the equation simplifies to:
The initial potential energy of the spring is given by the equation:
the Kinetic energy of the block is then given by the equation:
so we can now set them both equal to each other, so we get:
This new equation can be simplified if we multiplied both sides of the equation by a 2, so we get:
so now we can solve this for the final velocity, so we get:
Answer:8.3m/sec 30 sec,
Explanation:
A student practicing for a track meet, ran 250 m in 30 sec. a. What was her average speed? 250 m = 8.3 m/sec 30 sec.
