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:
Answer:
b. Static > sliding > rolling friction.
Explanation:
Static friction is greater than sliding friction. It takes more force to get an object to start sliding than to keep it sliding.
Sliding friction is greater than rolling friction. There are fewer points of contact for a round surface compared to a flat one.
Answer:
vf=94.4 m/s
Explanation:
acceleration is the final velocity minus initial velocity divided by time
a = (vf-vi)/t
Given:
a= 14.2 m/s^2
vi= 0 (at rest)
t = 6.6
Solve for vf
a = (vf-vi)/t
a*t=vf-vi
(14.2)*(6.6)=vf - 0
vf=94.4 m/s
The true statements are B and C.
This comes from the following facts:
Even when heat is added to a substance in a change of phase the temperature does not increases since this heat is latent heat.
Answer: A = square root (2/L)
Explanation: find the attached file for explanation
