It's called rifling, to stabilise the bullet.
The correct option is <u>D</u>.
Qualitative observations are observations that are made using our senses of sight, hearing, smell, taste and feel. These observations do not involve numbers or measurements of any kind.
The student's observations regarding the squirrel as is mentioned in options A, B and C involve measurements. Therefore these are not qualitative observations.
Option D, however, is made on the basis of sight, where the student observes the squirrel moving in a zigzag manner.
Therefore, of all the three observations, the student's observation that the squirrel ran in a zigzag pattern is the qualitative observation.
B) 7.87 m/s
The gravitational pull is the rate of change of velocity which is the acceleration. Formula for acceleration is;

Given:
• Initial velocity = 0m/s; I dropped the ball, and didn't throw it, so it was at rest firstly
• Time taken = 2.40s
• Acceleration = 3.28m/s^2
We're require to find the final velocity, at which the ball hit the ground with. Ignoring air resistance, keep in mind that the velocity of an object increases as it comes closer to the ground.


Something hot like a fire , an eye of a stove , and the sun