Describe two methods a researcher can use to avoid obtaining a nonrepresentative sample
1 answer:
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Answer:
The correct option is;
B Move both the balloon and mass 10 cm to the right
Explanation:
Given that the system is in equilibrium, we have;
Force of balloon = ↑
Force of mass = ↓
The direction of the balloon is having an upward motion which gives a clockwise moment or motion to the rod while the direction of the force of the mass weight is downwards, giving the rod an anticlockwise moment
for the rod to rotate clockwise, the moment of the balloon should be larger than that of the rod
At the present equilibrium we have;
× 30 =
× 20
Therefore;
= 1.5×
Moving both balloon and mass 10 cm to the right gives;
The moment of the balloon = × (30 - 10) =
× 20 = 20×
,
The moment of the mass = × (20 - 10) =
× 10
When we substitute = 1.5×
in the moment equation for the mass, we have;
The moment of the mass = × 10 = 1.5×
×10 = 15×
Therefore, the balloon now has a larger momentum than that of the mass and the rod will rotate clockwise.
Answer:
The height of the package when it was released was 1102.5 meters
Explanation:
A package is dropped from a hovering helicopter
Dropped means the initial velocity of the package is zero
The package takes 15 seconds to strike the ground
Ignore the air resistance
We need to know the height of the package when it was released
, where h is the height of the package
from the ground, u is the initial velocity, g is the acceleration of gravity
and t is the time
u = 0 , t = 15 seconds , g = 9.8 m/s²
h = 1102.5 meters
<em>The height of the package when it was released was 1102.5 meters</em>
Answer:
Its Answer is 10 s.
Explanation:
As acceleration is defined as time rate of change of velocity. So,
a = ÷ t
2 = (20 - 0 ) ÷ t
2 = 20 ÷ t
t = 20 ÷ 2
t = 10 s
We have put initial velocity as zero because body is starting from rest.
<em>Hope it helps.</em>