A, electromagnetic radiation
Answer:
System D --> System C --> System A --> System B
Explanation:
The gravitational force between two masses m1, m2 separated by a distance r is given by:

where G is the gravitational constant. Let's apply this formula to each case now to calculate the relative force for each system:
System A has masses m and m separated by a distance r:

system B has masses m and 2m separated by a distance 2r:

system C has masses 2m and 3m separated by a distance 2r:

system D has masses 4m and 5m separated by a distance 3r:

Now, by looking at the 4 different forces, we can rank them from the greatest to the smallest force, and we find:
System D --> System C --> System A --> System B
Answer:
t = 2.13 s
Explanation:
given,
height of the building = 22.3 m
horizontal distance = 127 m
acceleration due to gravity = 9.8 m/s²
time for which ball is in motion = ?
using equation of motion

initial velocity is zero



t = √4.551
t = 2.13 s
A vibrating stretched string has nodes or fixed points at each end. The string will vibrate in its fundamental frequency with just one anti node in the middle - this gives half a wave.

Rearranging for the wavelength



Therefore the longest wavelength standing wave that it can support is 14m