Answer:
A. 40 cm
Explanation:
For a curved mirror, the focal length is twice the radius of curvature of the mirror. In formula:
![f=2R](https://tex.z-dn.net/?f=f%3D2R)
where
f is the focal length
R is the radius of curvature
The concave mirror in this problem has a radius of curvature of
R = 20 cm
so, its focal length is
![f=2R=2(20 cm)=40 cm](https://tex.z-dn.net/?f=f%3D2R%3D2%2820%20cm%29%3D40%20cm)
If it's volume changes when you move it to the new container it would be a solid
The middle one on the list is the correct one.
The first one ... distance divided by time ... is Speed, not force.
The third one ... mass times velocity ... is Momentum, not force.
Answer:
acceleration a = 1.04 m/s2
Explanation:
Assume the train has a speed of 23m/s when the last car passes the railway workers. Once this happens the last car would have traveled a total distance of the 180m distance between the railway worker standing 180 m from where the front of the train started plus the 75m distance from the first car to the last car:
s = 75 + 180 = 255 m
We can use the following equation of motion to find out the distance traveled by the car:
where v = 23 m/s is the velocity of the car when it passes the worker,
= 0m/s is the initial velocity of the car when it starts, a m/s2 is the acceleration, which we are looking for.
![23^2 - 0^2 = 2*a*255](https://tex.z-dn.net/?f=23%5E2%20-%200%5E2%20%3D%202%2Aa%2A255)
![510a = 529](https://tex.z-dn.net/?f=510a%20%3D%20529)
![a = 529 / 510 = 1.04 m/s^2](https://tex.z-dn.net/?f=a%20%3D%20529%20%2F%20510%20%3D%201.04%20m%2Fs%5E2)