To measure the strength of an earthquake, you can use either a Richter scale or Mercalli scale. Richter scale uses the amplitued of the wave and the distance from the source. Mercalli scale uses observations of people and is not considered to be scientific as Richter scale.
2nd and only 2nd option is right
Answer:
2.5 m/s
Explanation:
Mechanical energy is the sum of the potential and kinetic energy.
E = PE + KE
E = mgh + ½mv²
172.1 J = (7.26 kg) (9.8 m/s²) (2.1 m) + ½ (7.26 kg) v²
v = 2.5 m/s
Answer: A (
,309.8°)
B (2
, 315°)
C (
, 26.56°)
Explanation: To transform rectangular coordinates into polar coordinates use:
and 
For point A:




°
Point A is in the II quadrant, so we substract the angle for 360° since it is in degrees:

309.8°
Polar coordinates for point A is (
, 309.8°)
For point B:





°
Point B is in IV quadrant, so:

315°
Polar coordinates for point B is (
, 315°)
For point C:





26.56°
Polar coordinates for point C is (
, 26.56°)
The answer is option A.
Centripetal force is always directed towards the centre and does not change the speed of the body,but there is a change in the direction.