Explanation:
Since the balloon is not accelerating means that the net force on the balloon is zero. This implies that the weight of balloon must be equal to the buoyant force on balloon.
Hence, the buoyant force equals the weight of air displaced by the balloon, also 20,000 N.
Weight of the air displaced = density of air × volume
The density of air at 1 atm pressure and 20º C is 1.2 kg/m³
the volume V = 20,000/(1.2×9.8) = 1700 m³
The formula for average speed is S=D/T
1. S=72m/37s
Divide
S= 1.94
Kira's average speed is 1.94m/s.
2. S=7.5km / 1.5h
S=5
Your average speed is 5km/h
3. S=1260km/3.5h
S=360
The airplanes average speed is 360km/h
Forces are exerted I believe : all of the above
The action force might be Tyler throwing the ball
I don't know the last one
The equation of motion of a pendulum is:
where it its length and is the gravitational acceleration. Notice that the mass is absent from the equation! This is quite hard to solve, but for <em>small</em> angles (), we can use:
Additionally, let us define:
We can now write:
The solution to this differential equation is:
where and are constants to be determined using the initial conditions. Notice that they will not have any influence on the period, since it is given simply by:
This justifies that the period depends only on the pendulum's length.