<u>Answer:</u> A. constant
Without any air resistance, as the golf ball falls into the well, its speed is constant.
<u>Explanation:</u>
Given that when the ball is released,<em>there is no air resistance acting on ball. So the ball is freely falling.
</em>
The only force acting on the freely falling body is the gravitational force pulling the body towards the centre of the earth.Here the only acceleration acting on the body is the <em>acceleration due to gravity.</em>
The acceleration due to gravity is 
. so through out the journey of the ball,the acceleration is . <em>So as the acceleration is constant, the speed is also constant.</em>
M/sec = 112 km / 1 hr / 1 min / 1000 meters
hr / 60 min / 60 sec / 1 km
So the answer is = 31.1 meters/sec
Answer: Aluminium
Explanation: Aluminium metal has a lower density than copper. So, for the same volume of metal used to build a model airplane, the aluminium plane would be very lightweight while that of copper would be heavy. The lightweight airplane will fly easily.
Answer: K and Na
Explanation:
Potassium and Sodium have a chemical symbol of K and Na respectively.
They have similar chemical properties because both
- have only one valence electron,
- form univalent positive ion when they donate their lone outermost electron as shown below
Na --> Na+ + e-
K --> K+ + e-
- are good reducing agents
- react with cold water vigorously to liberate hydrogen gas and form alkalis, so they are known as alkali metals.
- K and Na are placed in Group 1 of the periodic table.
Thus, unlike the other pairs given, K and Na, have the most similar chemical properties
