Explanation:
The density of the material is given by,
Density = 
Case 1: Rock
Density = 
Density = 
Density = 2000 
Case 2: Pillow
Density = 
Density = 
Density = 20 
Case 3: Bottle of Soda
Density = 
Density = 
Density = 1000 
Case 4: Load of bread
Density = 
Density = 
Density = 100 
Thus, rock and bottle of soda has maximum density.
Answer:
The centripetal acceleration of the runner is
.
Explanation:
Given that,
A runner completes the 200 m dash in 24.0 s and runs at constant speed throughout the race. We need to find the centripetal acceleration as he runs the curved portion of the track. We know that the centripetal acceleration is given by :

v is the velocity of runner

Centripetal acceleration,

So, the centripetal acceleration of the runner is
. Hence, this is the required solution.
We are given information:
m = 0.0450 kg
Δv = 25.2 m/s
Δt = 1.95 ms = 0.00195s
To find force we use formula:
F = m * a
a is acceleration. To find it we use formula:
a = Δv / Δt
a = 25.2 / 0.00195
a = 12923.1 m/s^2
Now we can find force:
F = 0.0450 * 12923.1
F = 581.5 N
To check the effect of the ball's weight on this movement we need to calculate it and then compare it to this force.
W = m * g
W = 0.0450 * 9.81
W = 0.44145 N
We can see that weight is much smaller than the applied force so it's influence in negligible.
Not pushing yourself hard enough is the answer since your heart rate doesn't even hit your lower minimum.
Pushing yourself to the limit is at your max heart rate.
Just at the right spot is at your max heart rate.
Pushing yourself too hard is above your max heart rate.
Hydrogen, helium, and carbon.