Answer:
Explanation:
We shall apply conservation of mechanical energy law to solve the problem .
loss of height = L ( 1 - cos 37 ) where L is length of rope
loss of potential energy at the bottom = gain of kinetic energy .
mg L ( 1 - cos 37 ) = 1/2 m v² where v is velocity at the bottom
v² = 2 L g ( 1 - cos 37 )
= 2 x 10 x 9.8 ( 1 - cos 37 )
= 39.46
v = 6.28 m /s
Answer:
Option (a)
Explanation:
We will discard options that don't fit the situation:
Option b: <em>Incorrect </em>since if the driver "hits the gas" then velocity is augmenting and it's not constant.
Option c and d: <em>Incorrect </em>since the situation doesn't give us any information that could be related directly to the terrain or movement direction.
Option a: Correct. At <em>stage 1</em> we can assume the driver was going at constant speed which means acceleration is constantly zero. At <em>stage 2 </em>we can assume the driver augmented speed linearly, this is, with constant positive acceleration. At <em>stage 3 </em>we can assume the driver slowed the speed linearly, with constant negative acceleration.
The true option is a) they form a 90 degree angle.
Pythagorean theorem is valid for right triangles, which is what you can form when the two vectors have a 90 degree angle.
Regarding the other options:
b) They are equal in magnitude: this is not a condition because Pythagoream theorem is valid for any magnitude as long as the angle is 90°C.
c) They have the sam directions: false, because if the two vectors have the same directions the magnitud is the sum of the two magnitudes.
d) They are parallel: false for a similar reason that c) taking into account if they have the same direction or are opposed. .