D. The string vibrated because of resonance, which happened because the tuning fork and guitar string have same natural frequency.
If you dropped a ball from any height, and measured its distance from the ground at any regular interval while it's falling, the graph of that distance versus time would be a graph that curves downward.
-- The ball is falling down. As time goes on, it gets closer and closer to the ground. Its remaining distance from the ground keeps decreasing, so the line on the graph slopes down.
-- The speed of the ball keeps increasing (it accelerates) because of the gravitational force on it. As time goes on, it covers more of the remaining distance during each interval than it did in the previous interval. The downward slope of the graph keeps increasing.
Answer:
reduce the velocity of collision
Answer:
The mass of the cargo is 
Explanation:
From the question we are told that
The radius of the spherical balloon is 
The mass of the balloon is
The volume of the spherical balloon is mathematically represented as

substituting values


The total mass the balloon can lift is mathematically represented as

where
is the density of helium with a value of

and
is the density of air with a value of

substituting values


Now the mass of the cargo is mathematically evaluated as

