Answer:
d) the amount of work is the same whether the bag is moved all at once or in two stages, provided the total height lifted is the same in either case.
Explanation:
While moving the bag to the shelf in one shot we can say that the total work done is given as
here we know that
2H = total height raised by the bag
now when we raise the bag to first shelf and then move it to next shelf
then we will have
![W = W_1 + W_2[tex][tex]W = mgH + mgH](https://tex.z-dn.net/?f=W%20%3D%20W_1%20%2B%20W_2%5Btex%5D%3C%2Fp%3E%3Cp%3E%5Btex%5DW%20%3D%20mgH%20%2B%20mgH)
so the correct answer will be
d) the amount of work is the same whether the bag is moved all at once or in two stages, provided the total height lifted is the same in either case.
Answer:
See below
Explanation:
Vertical position = 45 + 20 sin (30) t - 4.9 t^2
when it hits ground this = 0
0 = -4.9t^2 + 20 sin (30 ) t + 45
0 = -4.9t^2 + 10 t +45 = 0 solve for t =4.22 sec
max height is at t= - b/2a = 10/9.8 =1.02
use this value of 't' in the equation to calculate max height = 50.1 m
it has 4.22 - 1.02 to free fall = 3.2 seconds free fall
v = at = 9.81 * 3.2 = 31.39 m/s VERTICAL
it will <u>also</u> still have horizontal velocity = 20 cos 30 = 17.32 m/s
total velocity will be sqrt ( 31.39^2 + 17.32^2) = 35.85 m/s
Horizontal range = 20 cos 30 * t = 20 * cos 30 * 4.22 = 73.1 m
Momentum is a vector, although we don't hammer on that. In order to completely describe a momentum, you need a magnitude AND a direction ... just like force and velocity.
So choice #2 is the magnitude of a momentum, without its direction.
<em>Choice #3</em> is the full package, with both the magnitude and the direction.
Choice #1 has units of energy, and choice #4 has units of acceleration, so neither of those can be it.
Answer:
By opening the door, Elijah is using the chemical energy, which he obtained from eating food to do work. Thus, he is converting chemical energy to mechanical energy.
Stretching the spring by opening the screen door convert the potential energy which is stored in the spring to kinetic energy.
Overall there is conversion of chemical energy to potential energy.
By letting the door go, Elijah is using chemical energy. By snapping shut, the door is converting potential energy to kinetic energy. The overall energy change is conversion of chemical energy to kinetic energy.
Explanation:
