A 14m long ladder leans against the wall, making a 25 degree angle against the wall. it takes a 50kg person 9 seconds to climb to the top of the ladder, how much work was done?
Answers
Explanation:
Answer
There are four forces acting on the ladder of length L and making ?=53
degrees with the vertical smooth wall and on a horizontal rough floor.
1. the weight W=(10×9.8) = 98 N
acting downwards through the middle of the ladder
2. vertical reaction on the floor acting upwards, equal to W.
These two forces form a couple of magnitude
W(
2
L
)sin?
3. Normal reaction N on the wall (horizontal) at the top end of the ladder,
equal in magnitude to
4. Frictional force F acting horizontally at the bottom of the ladder.
These two forces form another couple equal to FLcos?.
Since the ladder is in equilibrium, the two couples must be equal, thus
W(
2
L
)sin? = FLcos?
From which we can solve for F
= (
2
W
)tan?
= (
2
98
) tan 53
0
= 65 N
Answer:
A 0.07 KB/S 30
There are four forces acting on the ladder of length Land making ?=53
degrees with the vertical smooth wall and
on a horizontal rough floor.
1. the weight W= (10x9.8) = 98 N =
acting downwards through the middle of
the ladder
2. vertical reaction on the floor acting upwards, equal to W.
These two forces form a couple of
magnitude
we)sin?
3. Normal reaction Non the wall
(horizontal) at the top end of the ladder,
equal in magnitude to
4. Frictional force Facting horizontally at the bottom of the ladder. These two forces form another couple
equal to FLcos?.
Since the ladder is in equilibrium, the two couples must be equal, thus
w")sin? = FLcos?
From which we can solve for F
W )tan?
98
= 2 ) tan 530
= 65 N