Answer:
A. Mass(only)
Explanation:
The correct answer is A because if the balloon is filled with air, it's filled with matter. Matter is anything that has space and occupies mass. The air occupies mass in the balloon but that doesn't mean that the balloon is heavier. People confuse themselves with mass and weight saying it means the same thing. Mass, like I said is the amount of matter an object contains whereas weight is how much an object weighs.
Answer:
Part a)

Part b)

Part c)

Explanation:
Part a)
As we know that there is no external torque on the system of two twins
so here we will use



Part b)
Since angular momentum is conserved here as there is no external torque
so we will have



Part c)
Work done by both of them = change in kinetic energy
so we have




The impact speed will be
v^2 = 2*9.8*1.3
v^2 = 25.48
v= 5.04 m/s
Hello,
The balloon sticks to a sweater after it has been rubbed against it because once you rub a balloon against the sweater, the balloon steals electrons from the sweater, which leaves the sweater positively charged and the balloon negatively charged.
Mark brainliest if helped!