Answer:
20cm
Explanation:
A convex lens has a positive focal length and the object placed in front of it produce both virtual and real image <em>(image distance can be negative or positive depending on the nature of the image</em>).
According to the lens equation
where;
f is the focal length of the lens
u is the object distance
v is the image distance
If the magnification is - 0.6
mag = v/u = -0.5
v = -0.5u
since v = 10cm
10 = -0.5u
u = -10/0.5
u =-20 cm
Substitute u = -20cm ( due to negative magnification)and v = 10cm into the lens formula to get the focal length f

Hence the focal length of the convex lens is 20cm
It is 72 km/h
I hope it helps
Answer:
18.60 m/s
Explanation:
Original momentum = mv = 4000 with m = 115
after collision m = 115 + 100 = 215 kg
but the total momentum is still the same (conserved)
4000 = 215 v shows v = 18.60 m/s
Answer:
30 kilometers is a reasonable measurement