The energy of the ski lift at the base is kinetic energy:
where m is the mass of the ski lift+the people carried, and
is velocity at the base.
As long as the ski lift goes upward, its velocity decreases and its kinetic energy converts into potential energy. Eventually, when it reaches the top, its final velocity is v=0, so no kinetic energy is left and it has all converted into gravitational potential energy, which is
where
and h is the height at the top of the hill.
So, since the total energy must conserve, we have
and so
from which we find the height:
Answer: Air resistance and/or drag.
Explanation: The parachute adds drag to the parachutist, thus making him fall slower and safely to the ground.
Answer:
0.453 m/s
Explanation:
Assuming the handle has diameter of 0.4 m while inner part diameter is 0.1 m then the circumference of outer part is 
where d is diameter and subscript h denote handle. By substituting 0.4 for the handle's diameter then cirxumference of outer part is 
The rate of rotation will then be 1.81/1.256=1.441 rev/s
Similarly, circumference of inner part will be 
where subscript i represent inner. Substituting 0.1 for inner diameter then
The rate of rotation found for outer handle applies for inner hence speed will be 0.3142*1.441=0.453 m/s
Answer: 11369.46 m/s
Explanation:
We have the following data:
is the mass of the bowling ball
is the velocity of the bowling ball
is the mass of the ping-pong ball
is the velocity of the ping-pong ball
Now, the momentum 
of the bowling ball is:
(1)
(2)
And the momentum 
of the ping-pong ball is:
(3)
If the momentum of the bowling ball is equal to the momentum of the ping-pong ball:
(4)
(5)
Isolating :
(6)
(7)
Finally:
Answer:
- on the moon, they will fall at the time
- on earth, the coin will fall faster to the ground
Explanation:
A coin and feather dropped in a moon experience the same acceleration due to gravity as small as 1.625 m/s², and because of the absence of air resistance both will fall at the same rate to the ground.
If the same coin and feather are dropped in the earth, they will experience the same acceleration due to gravity of 9.81 m/s² and because of the presence of air resistance, the heavier object (coin) will be pulled faster to the ground by gravity than the lighter object (feather).
