Answer:
There is no mechanical advantage
Explanation:
The mechanical advantage is possible only when the force needed to lift a load is lesser than the weight of the load.
For example, is we have a mechanical advantage of 2, the force needed to lift will be 1/2 of the weight of the load, and if we have a mechanical advantage of 4, the force needed will be 1/4 of the weight of the load.
In the attached image there are clear examples of mechanical advantage with pulleys.
It would be true. Excess radiation causes cancer.
Decreases density because gases have less density than liquids
Answer:
16.2 days
Explanation:
Find the number of halflives:
1/2 * 1/2 = 1/4 so <u>two</u> halflives have passed
2 * 8.1 days = 16.2 days
Answer:
The air resistance on the skydiver is 68.6 N
Explanation:
When the skydiver is falling down, there are two forces acting on him:
- The force of gravity, of magnitude
, in the downward direction (where m is the mass of the skydiver and g is the acceleration due to gravity)
- The air resistance,
, in the upward direction
So the net force on the skydiver is:

where
m = 7.0 kg is the mass

According to Newton's second law of motion, the net force on a body is equal to the product between its mass and its acceleration (a):

In this problem, however, the skydiver is moving with constant velocity, so his acceleration is zero:

Therefore the net force is zero:

And so, we have:

And so we can find the magnitude of the air resistance, which is equal to the force of gravity:
